Invasion of Astro-Monster (怪獣大戦争,   Kaijū Daisensō?, lit. Great Monster War) is a 1965 tokusatsu kaiju film produced by Toho Company Ltd., and the sixth installment in the Godzilla series as well as the Showa series. The film was released to Japanese theaters on December 19, 1965.

Invasion of Astro-Monster was directed by Ishiro Honda, produced by Tomoyuki Tanaka, Henry G. Saperstein, and Reuben Bercovitch, and written by Shinichi Sekizawa. This film follows Ghidorah, the Three-Headed Monster, and details Ghidorah's reemergence, alongside an extraterrestrial takeover of Earth by an alien race known as Xiliens.

A sequel to this film, Ebirah, Horror of the Deep, was released on December 17, 1966.


During a manned mission to Planet X behind Jupiter, the astronauts encounter inhabitants called Xiliens who ask to borrow the two Earth-bound Monsters Zero-One (Godzilla) and Zero-Two (Rodan) to combat their own terror, Monster Zero.

At the outset of the movie, the two-man spacecraft, crewed by one Japanese and one American (Fuji and Glenn), is approaching Jupiter to visit the newly-discovered "Planet X", which inexplicably maintains a position directly behind Jupiter. The planet is rather dark, but still lit up enough to be visible and for it to be possible to navigate its surface. The spacecraft lands, and the astronauts disembark.

One astronaut vanishes, and the other wonders where he, and the spacecraft, have gone, and then a flat voice intones to him, instructing him where to go. The astronauts are led through subterranean corridors to the office of the Controller of Planet X.

The spacecraft is safe, he assures them, and indicates that they are about to be attacked. The astronauts recognize the attacking creature, King Ghidorah. After a brief black-out, when the astronauts are cut off from being able to see and hear the Controller, they are assured that the monster, known as Monster Zero, has left.

The Controller says that they want Earth's help: to be allowed to capture Monsters Zero One and Zero Two, known to Earthmen as Godzilla and Rodan. In return, Planet X will gift humanity with a wonder drug that cures all diseases. The astronauts agree to return to Earth with the proposal. As they lift off, they say on the radio to the Controller, "We're glad we found friends on Planet X."

Meanwhile, Fuji's sister has a boyfriend, Tetsuo, who's invented a personal alarm he thinks women could use to summon assistance if they're endangered. It creates a horrific loud noise that can be heard blocks away, and wonders why nobody's interested in buying it, but then a Miss Namikawa comes and makes an offer to buy it as an educational device, but keeps putting Tetsuo off on completing the deal.

Fuji and Glenn arrive home, and tell their superiors of the offer by Planet X. Scientists begin searching for Godzilla and Rodan. Then, the Controller of Planet X makes mysterious appearances on Earth, and Glenn becomes suspicious about Planet X. The Controller finally makes his appearance overt, "apologizes" for his unannounced presence, and offers to help locate the two monsters. Two Planet X spacecraft rapidly fly off and extract the two monsters.

Glenn, Fuji and one of their superiors are invited aboard a spacecraft to accompany the Controller back to Planet X, a trip that takes only a few hours; the Controller says that soon they'll be able to travel as fast as light. On reaching Planet X, there is almost immediately an attack by King Ghidorah, and the two from Earth are released to battle it. King Ghidorah is driven off, Godzilla dances a victory jig, and the Controller exults about that. He presents a box that, he says, contains information about the miracle drug, and presents the three men with a faithful duplicate of their spaceship so they can fly home.

On arrival, the box is taken to a special international meeting and is opened to find a reel-to-reel tape. It is loaded onto a machine and set up to play. When the speakers remain silent for a long period, some wonder if the systems are compatible, but others say their system is exactly the same as ours. Finally, there is a beep, and the voice begins. "This is the Controller of Planet X. You will listen to my instructions..." It is an ultimatum to surrender to Planet X.

The aliens arrive, destroy the spacecraft, and threaten to release the three creatures, which are now all under Planet X's control. In a show of confidence, the aliens even betray the method of control: magnetic waves. The Earth scientists realize that they could exploit this information, and work rapidly to find a way to disrupt those magnetic waves, while in the meantime, Earth's armies fight nearly in futility with conventional weapons as the monsters wage most of their destruction against Japan.

Tetsuo, meanwhile, is dissatisfied with the lack of progress on his device, and his inability to get Miss Namikawa to tell him what's happening. He gets imprisoned by the Planet X soldiers. When Glenn, who was infatuated with Miss Namikawa, is also arrested after finding out something about her - she's from Planet X and all their women are virtually identical, he and Tetsuo put clues together. Namikawa gave Glenn, before she was disintegrated by a Planet X soldier, a letter, and in it she says that one simple sound will destroy the people of Planet X. It is the sound made by Tetsuo's "lady beware alarm". He still has the prototype, takes it out and sets it off. It upsets and paralyzes the Planet X soldiers and Glenn can immobilize them and they escape.

They reach the space center scientists and explain about the device. Arrangements are made to broadcast it on all radio and television stations, a tactic that will be employed when the magnetic disruption devices are deployed.

The three monsters are removed from Planet X control, as Planet X spacecraft explode and personnel escape the noise by blowing up ships. Planet X withdraws its attempts to conquer Earth. Meanwhile, Godzilla attacks King Ghidorah with the aid of Rodan, forcing King Ghidorah into a retreat.

Glenn and Fuji are to be sent to Planet X again as ambassadors to seek peaceful relations.


Staff role on the left, staff member's name on the right.

  • Directed by Ishiro Honda
  • Written by Shinichi Sekizawa
  • Produced by Tomoyuki Tanaka, Henry G. Saperstein, Reuben Bercovitch
  • Music by Akira Ifukube
  • Cinematography by Hajime Koizumi
  • Edited by Ryohei Fujii
  • Production design by Takeo Kita, Akira Watanabe
  • Assistant directing by Koji Kajita
  • Special effects by Eiji Tsuburaya
  • Assistant Director of Special Effects Teruyoshi Nakano


Actor's name on the left, character played on the right.






Alternate titles

  • Great Monster War (Literal Japanese Title)
  • Great Monster War: King Ghidorah vs. Godzilla (怪獣大戦争 キングギドラ対ゴジラ?, Kaijū Daisensō: Kingu Gidora tai Gojira; Japan Re-Release Title)
  • Monster Zero (United States)
  • Invasion of the Astros (United States)
  • Godzilla vs. Monster Zero (Initial United States Home Video Title)
  • Invasion Planet "X" (Invasion Planet 'X'; France; French Belgium; Invasion Planeet X; Dutch Belgium)
  • The Monsters Invade the Earth (Los monstruos invaden la tierra; Spain)
  • Monsters of the Galaxies (Monstruos de las galaxias; Mexico)
  • Command from the Dark (Befel aus dem Dunkel; Germany)
  • The Invasion of the Astro Monsters (La invasion de los Astro-Monstruos; Mexico; L'invasione degli Astro Mostri; Italy)
  • Year 2000: The Invasion of the Astro Monsters (Anno 2000: L'invasione degli Astro Mostri; Italy)
  • The Space Monsters Are Attacking (Avaruushirviöt hyökkäävät; Finland)
  • Monster Invasion (Inwazja potworow; Poland)
  • Monsters Coming from Space (Uzaydan canavar geliyor; Turkey)
  • Attack from the Unknown (Utok z neznama; Czechoslovakia)
  • Invasion from Space (Invazija iz svemira; Yugoslavia)
  • War of the Monsters (A Guerra dos Monstros; Brazil)

Theatrical releases

  • Japan - December 19, 1965; March 17, 1971 (Re-Release)
  • United States - July 29, 1970
  • France - January 25, 1967
  • Germany - February 17, 1967
  • Mexico - May 23, 1968
  • Spain - July 15, 1968 (Madrid); March 10, 1969 (Barcelona)
  • Turkey - April 6, 1970
  • Italy - July 10, 1970
  • Poland - October 1970
  • Finland - August 17, 1973

U.S. release

American War of the Gargantuas and Monster Zero double bill poster

Invasion of Astro-Monster was released in North America by UPA and distributed by Maron Films in 1970 under the title Monster Zero. It played on a double bill with War of the Gargantuas. There were several alterations made:

  • Dialogue was dubbed to English.
  • The title song was changed, and some of Akira Ifukube's score was re-arranged.
  • Several sound effects were added.
  • Deleted: several shots of Godzilla's foot stepping on houses and huts.
  • Deleted: some short shots of the Xilien UFOs.
  • Deleted: Rodan blowing away tanks from the top of a hill.
  • Deleted: a scene of the Controller of Planet X speaking in the language of Planet X.

The American version runs 93 minutes, three minutes shorter than the Japanese version. In his book Japan's Favorite Mon-Star: An Unauthorized History of 'The Big G', Steve Ryfle says "The Americanization...is respectful to the original Japanese version."

In the original Japanese version of this movie, Nick Adams' original voice was dubbed over by Japanese voice actor Goro Naya. However, in the re-edited American version and the unedited international version, Nick Adams' voice wasn't dubbed over.

Box Office

When Invasion of Astro-Monster was first released on December 19, 1965, it received an attendance of 3,780,000. On its March 17, 1971 re-issue, it sold 350,000 tickets, adding up to a rough total of 5,130,000 attendees.

When the film was released in the U.S. in 1970, double-billed with War of the Gargantuas, it gained $3,000,000.


Invasion of Astro-Monster is very popular among fans, often dubbed a classic due to its extraordinary sci-fi story, special effects, plot, and cast.

Home media releases

Distributor Released Region Language Format Misc.
Simitar[1] May 6, 1998 Region 1 English (Dolby Digital 1.0)
English (Dolby Digital 5.1)
Full Screen
2.35:1 aspect ratio
93 minutes run time
1 disc
American version
Toho 2003 Region 2 Japanese N/A N/A
Madman 2005 Region 4 N/A N/A N/A
Classic Media[2] July 1, 2012 Region 1 English
Multiple formats
1.66:1 aspect ratio
94/93 minutes run time
1 disc
Japanese version
American version


  • Mothra was originally planned to make an appearance in this film but was cut due to budget constraints.
  • This film marks the very first appearance of an alien race in a Godzilla film.
  • During the scenes where Godzilla and Rodan are attacking, stock footage from Rodan is used, specifically from the scene where Rodan blows over a train and the scene where two soldiers are blown away.
  • An updated version of the "Frigate March" from the soundtrack for the original Godzilla film is heard multiple times in this film, including during the opening credits and the scene where the Xiliens' mind control is broken.
  • Godzilla's victory dance from this film appears as an unlockable attack in the 2014 Godzilla video game that can be used by Godzilla, Godzilla 1964, and Burning Godzilla.


  1. (May 6, 1998). Godzilla vs. Monster Zero Amazon. Retrieved July 4, 2017
  2. (July 1, 2012). Invasion of Astro-Monster Amazon. Retrieved July 4, 2017
Film media
Godzilla films
King Kong films
Mothra films
Gamera films
Other films
Cancelled or scrapped films