Although cross-sectional studies suggest considerable influence of menopause on serum lipids and lipoproteins in women, it is not exactly clear. During our 7-year longitudinal study, serum concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides and low-density lipoprotein (LDL) cholesterol were measured in 16 healthy perimenopausal women (aged 47-56 years at menopause) who had undergone annual examinations 4 years before and 3 years after menopause under a health examination system in Osaka. Longitudinal design enabled us to study the natural course of serum lipids and lipoproteins. The results show that from 4 years before to 1 year after menopause, the serum concentration of total cholesterol and LDL cholesterol increased on average by 25 mg/dl (14%) and 20 mg/dl (19%), respectively. Serum concentrations of triglycerides and of HDL cholesterol remained virtually unchanged during the perimenopausal and postmenopausal periods. It was concluded that serum lipids and lipoproteins are thus significantly altered as a consequence of menopause, resulting in a more atherogenic profile in the postmenopausal period.