The serum concentrations of triglycerides, cholesterol, and free glycerol were determined in 23 climacteric women, before and after the administration of three different steroid drugs. Each drug was given within a period of 12 weeks (3 cycles). Period I: Norgestrel, 0.5 mg daily from the 12th to 21st day of each cycle. Period II: Oestradiol-valerate (Progynon) 2 mg daily from the 2nd to 21st day of each cycle. Period III: Oestradiol-valerate 2 mg from the 1st to 11th day followed by oestradiol-valerate 2 mg+0.5 mg dl-norgestresl from day 12 to 21 of each cycle (Cycloprogynon). A significant decrease in triglycerides was observed following the administration of norgestrel and Cycloprogynon, whereas oestradiol-valerate had no effect on the triglyceride levels. On the other hand, oestradiol-valerate, following a period of norgestrel, produced an increase in serum cholesterol levels.