The purpose of this study was to compare, by a randomized double-blind study, involving 30 women with either acne or mild hirsutism, the effects on plasma androgens and lipoproteins, of two hormonal preparations used in acne and ensuring reliable contraception, namely Diane R (cyproterone acetate 2 mg and ethinylestradiol 50 μg per pill- D-50) and Diane 35 (cyproterone acetate 2 mg and ethinylestradiol 35 μg per pill - D-35). Both drugs, used over a 6-month period (treatment cycle of 21 days with a pill-free interval of 7 days), induced an impressive decrease of free testosterone levels and of 5α-androstane-3α, 17β-diol-glucuronide, a parameter of peripheral androgen formation; also dehydroepiandrosterone sulfate levels decreased significantly. Except for an increase of both total T and dihydrotestosterone and as well as for a more important increase in SHBG levels during treatment with D-50, consequences of its more pronounced estrogen dominance in comparison to D-35, the effects of both drugs on androgen levels were similar. The effects on lipids were characterized by a non-significant increase of total cholesterol and a significant increase of HDL-C, HDL2-C and Apo-Al lipoproteins, which were somewhat more pronounced during D-50 treatment. Triglycerides increased significantly during D-50 but hardly during D-35 treatment, whereas HDL-C LDL-C increased similarly during treatment with either drug. It is concluded that, being as efficient as D-50 in treatment of acne and hirsutism and taking into account its reliable contraceptive effects, without unfavourable effects, as far as atherogenesis is concerned, on plasma lipids, D-35 is to be preferred over D-50.