One of several giant-size comic books that supplemented Marvel's regular 36-page, 12-cent titles, Marvel Collectors' Item Classics was published first as an annual publication in 1965. That first issue, dated February 1965, reprinted The Fantastic Four #2 (Jan. 1962) and The Amazing Spider-Man #3 (July 1963), as well as the Ant-Man story from Tales to Astonish #36, and the first "Tales of Asgard" featurette, from Journey into Mystery #97 (Oct. 1963). It was a sister publication of what was then the annual, giant-size reprint comic Marvel Tales.
MCIC became a bimonthly series beginning with issue #2 (April 1966), which reprinted The Fantastic Four #3 (March 1962), The Amazing Spider-Man #4 (Sept. 1963), and the Ant-Man story from Tales to Astonish #37 (Nov. 1962).
Dropping Spider-Man the following issue — with that superhero's stories going on to anchor Marvel Tales — the comic began reprinting what would be its regular line-up: The Fantastic Four, The Incredible Hulk, Iron Man stories from Tales of Suspense, and Doctor Strange stories from Strange Tales. Six issues included short semi-anthological "Tales of the Watcher" science-fiction stories hosted by and sometimes featuring Uatu, the Watcher.
The reprints were generally in serial order, with occasional skips; missing, for instance, are The Fantastic Four #5-6, already reprinted in Fantastic Four Annual #2-3 (1964–1965); #11, already partly reprinted in Annual #3; #12, never reprinted at the time; #19, reprinted in heavily edited form in the 1967 promotional one-shot America's Best TV Comics; and #25-26, reprinted in Fantastic Four Annual #4 (1966).
The covers of issues #1-11 each reprinted two to four covers of the comics reprinted inside. Issues of The Incredible Hulk were not reprinted in full, but generally as chapters spread across two to three issues apiece.