In transsexual people, cross-sex hormone therapy is an important component of medical treatment. In male-to-female transsexuals, feminizing effects should be achieved before irreversible sex reassignment surgery (SRS) is considered. The most common treatment regimen in male-to-female transsexuals is a combination of ethinyl oestradiol and cyproterone acetate, with the exception of transdermal oestradiol-17beta in individuals over the age of 40. The mortality and morbidity rates with this treatment regimen have been reported in more than 800 patients. Typical side effects include venous thrombosis, elevated liver enzymes, symptomatic gallstones, hyperprolactinaemia and depression. Sixty male-to-female transsexuals were treated with monthly injections of gonadotropin-releasing hormone agonist (GnRHa) and oral oestradiol-17beta valerate for 2 years to achieve feminisation until SRS. There was a significant decline in gonadotropins, total testosterone and calculated free testosterone. In general, the treatment regimen was well accepted. An equal increase in breast size was achieved compared to common hormone therapy. Two side effects were documented. One, venous thrombosis, occurred in a patient with a homozygous MTHFR mutation. One patient was found to be suffering from symptomatic preexisting gallstones. No other complications were documented. Liver enzymes, lipids, and prolactin levels were unchanged. Significantly increased oestradiol and SHBG serum levels were detectable. In addition, an increase in bone mass density, in the femoral neck and lumbar spine, was recorded. We conclude that cross-sex hormone treatment of male-to-female transsexuals using GnRHa and oestradiol-17beta valerate is effective, and side effects and complication rates can be reduced using the treatment regimen presented here.