Objective: In the Netherlands, it is considered good medical practice to offer patients with gender identity disorder the option to undergo hormonal and surgical sex reassignment therapy. A liberalization of treatment guidelines now allows for such treatment to be started at puberty or prepuberty. The question arises as to what extent gender identity disorder can be reliably distinguished from a cross-gender identification that is secondary to other psychiatric disorders. Method: The authors sent survey questionnaires to 382 board-certified Dutch psychiatrists regarding their experiences with diagnosing and treating patients with gender identity disorder. Results: One hundred eighty-six psychiatrists responded to the survey. These respondents reported on 584 patients with cross-gender identification. In 225 patients (39%), gender identity disorder was regarded as the primary diagnosis. For the remaining 359 patients (61%), cross-gender identification was comorbid with other psychiatric disorders. in 270 (75%) of these 359 patients, cross-gender identification was interpreted as an epiphenomenon of other psychiatric illnesses, notably personality, mood, dissociative, and psychotic disorders. Conclusions: These data suggest that there is little consensus, at least among Dutch psychiatrists, about diagnostic features of gender identity disorder or about the minimum age at which sex reassignment therapy is a safe option. Therapy options proposed to patients with gender identity disorder appear to depend on personal preferences of psychiatrists. These results underline the need for more specific diagnostic rules in this area.