According to a news item in HR on 10 Jul 1936, M-G-M had just bought the rights to Erich Maria Remarque's newest novel, which was called Comrades in the item. The novel was published in Switzerland under the title Drei Kameraden in 1937, and under the title Three Comrades in the United States that same year. In Jul 1937 it was announced that Robert Taylor, Joan Crawford and James Stewart were to star in a motion picture adaptation that was earlier to have starred Spencer Tracy and Luise Rainer. At that time, R. C. Sherriff was working on a treatment for producer Joseph L. Mankiewicz. Sherriff is not credited elsewhere, and the extent of his participation in the completed film has not been determined. In Dec 1937, Tracy, Taylor and Robert Young were announced as the male leads, then, on 15 Jan 1938, James Stewart was again announced as one of the stars. According to a 17 Jan 1938 news item, Alan Curtis and Dennis O'Keefe were both testing for "the lead" in the picture. A HR news item on 23 Feb 1938, about two weeks after the start of production, noted that Joseph Ruttenberg was replacing Karl Freund as the photographer.
       Three Comrades was the only onscreen credit which author F. Scott Fitzgerald received for screenwriting. Comparison of the original Fitzgerald screenplay (which has been published in book form) with the released film indicates a significant number of specific changes in the story, as well as a shift to a slightly less somber mood. According to modern sources, in addition to Edward E. Paramore, who is credited as co-screenwriter on the film, M-G-M executives brought in writers David Hertz, Waldo Salt, Lawrence Hazard and Joseph L. Mankiewicz to work on the script. In the Fitzgerald original, or in revisions made by him, the setting of the film was the 1930s. There were many scenes in which Jews appeared and in which the issue of anti-Semitism figured prominently. In addition, Nazi brutalities were portrayed or alluded to, and the character of Dr. Becker was more prominent.
       According to information in the file on the film in the MPAA/PCA Collection at the AMPAS Library, many of the changes between the original script and the final one were requested by the Hays Office before approval was granted. Major changes were specifically required in the following areas: some lines of dialogue and situations that were considered too suggestive had to be toned down; no use of the Nazi emblem or mention of specific German leaders were to be used; a scene in which a book-burning takes place had to be removed; a "We are Jews" speech delivered by the character Dr. Becker was to be deleted; some additional lines of dialogue, situations and character names concerning Jews were to be deleted; when character Otto Koster kills the man who murdered the character Gottfried Lenz, care was to be taken to indicate that the killing was in self-defense, and Koster was not to "empty his Luger into the murderer's body." Additionally, suggestions were made to change the setting of the film from the 1930s to two or three years after the end of World War I. According to a 27 Jan 1938 letter sent to Louis B. Mayer by Joseph I. Breen, PCA director, the Hays Office suggested, "It might be better to make the Communists the 'Heavies'...do not indicate by emblem [Swastika] or uniforms that the period is other than following the war." Another suggestion offered by Breen was to delete a reference to Felix Mendelssohn. [The music of composer Mendelssohn, who was Jewish, was banned in Germany under the Nazi regime.]
       An article appeared in the magazine New Masses on 15 Feb 1938, a few days after the start of the film's production, entitled "Off-Color Remarque," in which the author charged that Breen, the head of the Legion of Decency and the German Consul General, Dr. George Gyssling, had met to discuss the film and decided among themselves what changes should be made in the story to make it less of an indictment against Nazi Germany than Remarque's original novel. The earliest letter in the MPAA/PCA file from Gyssling to Breen is dated 28 May 1937. In that letter, Gyssling inquired about the film adaptation, but Breen replied that the script had "not been submitted to us." No information in the file refers to any meetings between Breen and Gyssling, or between either of them and the local head of the Legion of Decency, concerning the film. On 22 Jan 1938, after the final script has been approved, Breen wrote to M-G-M: "The story, while dramatically sound and entertaining, is, inescapably, a serious indictment of the German nation and people and is certainly to be violently resisted by the present government in that country." When the film was released, most territories approved it without eliminations, according to the file, although Germany raised objections to the use of drums and those scenes were shortened. Margaret Sullavan received an Academy Award nomination as Best Actress for the film, but lost to Bette Davis for Jezebel. Trade reviews had negative comments about the released film. The HR reviewer called it "a combination of the magnificent and the deeply disappointing," and the Var reviewer said, "There must have been some reason for making this picture, but it certainly isn't in the cause of entertainment....despite all the draught of the star names, it's in for a sharp nosedive at the box office."