This wasn't director Paul Verhoeven's and screenwriter Gerard Soeteman's preferred project to work on. Verhoeven had hoped to do an adaptation of a major Dutch literary work, rather than an anecdotal novel about prostitution. However, Soeteman convinced him that they could make something acceptable out of it, and that they simply needed the work. Soeteman's instincts turned out correct, as the movie became a success, and it opened the way for their next project, the critically acclaimed and commercially successful literary adaptation Turkish Delight (1973).
In preparation of the movie, director Paul Verhoeven interviewed real prostitutes in Amsterdam's red-light district while screenwriter Gerard Soeteman studied some scientific papers on prostitution.
The Dutch title 'Wat Zien Ik ?' is Dutch slang (specifically from Amsterdam), expressing a sensation of mild surprise, roughly translating to "What have we here?"
Actor Albert Mol, author of the novel on which this film is based appears as Nel's blind date who ends up with pie in his face. His daughter Kika Mol plays one of the prostitutes.
Was originally intended as a pornographic movie before Paul Verhoeven and Gerard Soeteman turned it into a farcical comedy.