45 patients with prostatic cancer were treated conservatively with Turisteron at a dosage of 2 mg per week. After 2 months the serum levels of total testosterone were reduced to castration values and thereafter furthermore to 6% of the pretreatment values. The free testosterone (FT) serum level did show a decrease to 2%, while the binding capacity of the sexual hormone binding globulin (SHBG) was increased from 4,1% to 97,9%. The serum levels of the two gonadotropic hormones luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were decreased only to nearly 20% of the pretreatment value. The investigations confirm the definite "antiandrogenic" effect of Turisteron, which is 10-times higher than the antigonadotropic effect.