Puccini’s opera is based on several sources, specifically two American works: a magazine story by John Luther Long and a play by David Belasco, both titled Madame Butterfly. There is also evidence that Puccini was influenced by the French novel Madame Chrysanthème by Pierre Loti. The story by Long was somewhat biographical, based on his sister’s account of her travels to Japan. Belasco directly adapted Long’s story into the play Puccini saw in London in 1900. However, Long and Belasco never visited Japan themselves. Loti’s 1887 novel, on the other hand, is more autobiographical. He was briefly married to a Japanese woman, like his main character, Pierre, who is similar to the character of Pinkerton. In Loti’s version, Madame Chrysanthème, Pierre’s wife, does not die by suicide.

Long’s story, which appeared in the 1898 issue of Century Illustrated Monthly Magazine, offers a different ending from both Loti’s and Belasco’s/Puccini’s. In his version, Butterfly attempts suicide but does not die. Only in Belasco’s version does Butterfly die at the end of the play. This is the ending that Puccini emulates in his opera. Chadwick Jenkins, of Columbia’s Opera Project, states:  

The libretto of Madama Butterfly is one of those rare instances in operatic history where the text is actually an improvement over its sources.