Shaw said he wrote the play "to draw attention to the truth that prostitution is caused, not by female depravity and male licentiousness, but simply by underpaying, undervaluing and overworking women so shamefully that the poorest of them are forced to resort to prostitution to keep body and soul together."
He explained the source of the play in a letter to the Daily Chronicle on 28 April 1898:
Miss Janet Achurch [an actress and friend of Shaw’s] mentioned to me a novel by some French writer [Yvette by Guy de Maupassant] as having a dramatisable story in it. It being hopeless to get me to read anything, she told me the story... In the following autumn I was the guest of a lady [Beatrice Webb] of very distinguished ability—one whose knowledge of English social types is as remarkable as her command of industrial and political questions. She suggested that I should put on the stage a real modern lady of the governing class—not the sort of thing that theatrical and critical authorities imagine such a lady to be. I did so; and the result was Miss Vivie Warren ... Mrs. Warren herself was my version of the heroine of the romance narrated by Miss Achurch. The tremendously effective scene—which a baby could write if its sight were normal—in which she justifies herself, is only a paraphrase of a scene in a novel of my own, Cashel Byron's Profession (hence the title, Mrs Warren's Profession), in which a prize-fighter shows how he was driven into the ring exactly as Mrs. Warren was driven on the streets.