The purpose of our study was to compare the effects of cyclical versus continuous transdermal oestrogen replacement therapy on lipoprotein (a) (Lp(a)) and nitric oxide levels. The patients were randomly assigned into two groups. The first group received transdermal 17-beta oestradiol 50 mug/day for 21 days and the second group the same treatment on a continuous basis. Medroxyprogesterone acetate (10 mg/day orally) was added between the 14th and 25th days to each group. Lipoprotein (a) and nitric oxide levels were measured before the study and after six months. These values were compared using the Wilcoxon rank test within the groups and the unpaired t-test between the groups. Lipoprotein (a) levels decreased significantly in each group at the sixth month (p < 0.05). When compared between the groups, the decrease of lipoprotein (a) levels in the second group was more prominent at the sixth month (p < 0.05). Nitric oxide levels increased in each group after six months (p < 0.05). No difference in nitric oxide levels was observed between the groups before and after the therapy (p > 0,05). Continuous transdermal estradiol had a better effect on lipoprotein (a) levels than cyclical therapy The seven day pause in the 21-day administration did not affect nitric oxide levels negatively after six months.