This issue has variants.
in Fantastic! (IPC, 1967 series) #2 (25 February 1967)
in Los Hombres X (Editora de Periódicos La Prensa S.C.L., 1966 series) #1 (31 de enero de 1966)
in Marvel Super-Heroes (Marvel, 1967 series) #22 (September 1969)
in Son of Origins of Marvel Comics (Simon and Schuster, 1975 series) #[nn] (1975)
in Amazing Adventures (Marvel, 1979 series) #1 (December 1979)
in The Official Marvel Index to the X-Men (Marvel, 1987 series) #1 (May 1987)
in Marvel Masterworks (Marvel, 1987 series) #3 ([November] 1987), #3 ([November] 1987)
in Marvel Milestone Edition: X-Men #1 (Marvel, 1991 series) #[nn] (1991)
in Uncanny X-Men Masterworks (Marvel, 1993 series) #1 (February 1993), #1 (February 1993)
in X-Men Ashcan (Marvel, 1994 series) #[nn] (1994) [interior art page]
in Son of Origins of Marvel Comics Revised Edition (Marvel, 1997 series) #[nn] (November 1997)
in Marvel Masterworks: The X-Men (Marvel, 1998 series) #[1] (December 1998)
in Essential Uncanny X-Men (Marvel, 1999 series) #1 (September 1999) [black & white reprint]
in The 100 Greatest Marvels of All Time (Marvel, 2001 series) #5 (December 2001)
in Marvel Masterworks: The X-Men (Marvel, 2002 series) #1 (April 2002)
in Marvel Mini Comic Book X-Men #1 (Marvel, 2003 series) #[nn] (2003)
in Target X-Men Classic (Marvel, 2006 series) #[nn] (2006)
in Custom: Deal - Fox Home Entertainment (X-3 Stan Lee Comic) (Marvel, 2006 series) #1 (September 2006)
in The X-Men Omnibus (Marvel, 2009 series) #1 ([April] 2009), #1 ([April] 2009)First Appearance of X-Men and Magneto.
Disputed inker credit:
1. Sol Brodsky, from The Marvel Comics Index (Olshevsky 1981), The Official Marvel Index to the X-Men (Olshevsky 1987), and Official Index to the Marvel Universe (Vandal et al. 2009), and per Nick Caputo, Bob Ford, and this site’s original indexer;
2. Frank Giacoia per Carl Gafford;
3. Paul Reinman per Steve Whitaker.
Sources for letters credit are The Marvel Comics Index, The Official Marvel Index to The X-Men, and Official Index to the Marvel Universe.
in Marvel Tales Annual (Marvel, 1964 series) #2 (1965)
in Los Hombres X (Editora de Periódicos La Prensa S.C.L., 1966 series) #1 (31 de enero de 1966)
in Fantastic! (IPC, 1967 series) #1 (18 February 1967) [pages 1-10], #2 (25 February 1967) [pages 11-23]
in Capitan America (Editoriale Corno, 1973 series) #1 (24 Aprile 1973) [part 1]
in Son of Origins of Marvel Comics (Simon and Schuster, 1975 series) #[nn] (1975)
in Amazing Adventures (Marvel, 1979 series) #1 (December 1979) [pp. 1-12], #2 (January 1980) [pp. 13-23]
in The Marvel Saga (Marvel, 1985 series) #10 (September 1986) [excerpt]
in Marvel Masterworks (Marvel, 1987 series) #3 ([November] 1987)
in Uncanny X-Men Masterworks (Marvel, 1993 series) #1 (February 1993)
in X-Men: The Early Years (Marvel, 1994 series) #1 (May 1994)
in Marvel Special (Marvel Italia, 1994 series) #3 (Aprile 1995)
in Son of Origins of Marvel Comics Revised Edition (Marvel, 1997 series) #[nn] (November 1997)
in Marvel Masterworks: The X-Men (Marvel, 1998 series) #[1] (December 1998)
in Essential Uncanny X-Men (Marvel, 1999 series) #1 (September 1999) [black and white reprint]
in The 100 Greatest Marvels of All Time (Marvel, 2001 series) #5 (December 2001)
in Marvel Masterworks: The X-Men (Marvel, 2002 series) #1 (April 2002)
in Marvel Mini Comic Book X-Men #1 (Marvel, 2003 series) #[nn] (2003)
in Target X-Men Classic (Marvel, 2006 series) #[nn] (2006)
in Custom: Deal - Fox Home Entertainment (X-3 Stan Lee Comic) (Marvel, 2006 series) #1 (September 2006)
in The X-Men Omnibus (Marvel, 2009 series) #1 ([April] 2009)Comic includes 2 full page house ads for Amazing Spider-Man #4 and Sgt. Fury and His Howling Commandos #3.