Upon the book's publication in France in 1934, the United States Customs Service banned the book from being imported into the U.S. Frances Steloff sold copies of the novel smuggled from Paris during the 1930s at her Gotham Book Mart, which led to lawsuits. A copyright-infringing edition of the novel was published in New York City in 1940 by "Medusa" (Jacob Brussel); its last page claimed its place of publication to be Mexico. Brussel was eventually sent to jail for three years for the edition.
In 1950, Ernest Besig, the director of the American Civil Liberties Union in San Francisco, attempted to import Tropic of Cancer along with Miller's other novel, Tropic of Capricorn, to the United States. Customs detained the novels and Besig sued the government. Before the case went to trial, Besig requested a motion to admit 19 depositions from literary critics testifying to the "literary value of the novels and to Miller's stature as a serious writer". The motion was denied by Judge Louis A. Goodman. The case went to trial with Goodman presiding. Goodman declared both novels obscene. Besig appealed the decision to the Ninth Circuit of Appeals, but the novels were once again declared "obscene" in a unanimous decision in Besig v. United States.
In 1961, when Grove Press legally published the book in the United States, over 60 obscenity lawsuits in over 21 states were brought against booksellers that sold it. The opinions of courts varied; for example, in his dissent from the majority holding that the book was not obscene, Pennsylvania Supreme Court Justice Michael Musmanno wrote Cancer is "not a book. It is a cesspool, an open sewer, a pit of putrefaction, a slimy gathering of all that is rotten in the debris of human depravity."
Publisher Barney Rosset hired lawyer Charles Rembar to help Rosset lead the "effort to assist every bookseller prosecuted, regardless of whether there was a legal obligation to do so". Rembar successfully argued two appeals cases, in Massachusetts and New Jersey, although the book continued to be judged obscene in New York and other states.
In 1964, the U.S. Supreme Court, in Grove Press, Inc. v. Gerstein, cited Jacobellis v. Ohio (which was decided the same day) and overruled state court findings that Tropic of Cancer was obscene.
The book was banned outside the U.S. as well:
- In Canada, it was on the list of books banned by customs as of 1938. The Royal Canadian Mounted Police seized copies of the book from bookstores and public libraries in the early 1960s. By 1964, attitudes toward the book had "liberalized".
- Only smuggled copies of the book were available in the United Kingdom after its publication in 1934. Scotland Yard contemplated banning its publication in Britain in the 1960s, but decided against the ban because literary figures such as T. S. Eliot were ready to defend the book publicly.
- In Finland all printed copies of the Finnish versions of the book were confiscated by the state before the books were to be published in 1962. The book was not published there till 1970. The book was however available in Swedish and English.