Objective: The higher incidence of man‐to‐woman transsexuals compared to woman‐to‐man transsexuals varies markedly from country to country. This is the first survey of the sex ratio to be made in Germany. Method: It covers 1785 patients who between 1964 and 1998 were diagnosed as transsexual at the four largest German centres offering treatment. Results: From 1970 to 1994 the sex ratio remained constant at 2:1 in favour of man‐to‐woman transsexuals. Over the past 4 years, however, it has altered considerably and reached 1.2:1. Conclusion: Up to 1994 our results do not support the assumption that transsexualism is gradually becoming equally prevalent in both sexes. The drop in the sex ratio after 1994 can be explained either as a reduction of an overhang of male‐to‐female transsexuals or as an artificial phenomenon caused by recent developments in therapy and by the views of transsexuals' groups on the treatment they are offered.