This review outlines the changes in serum lipoprotein (Lp) concentrations at the menopause. The effect of hormone replacement therapy with estrogen and a variety of progestogens is illustrated by a number of recent studies. Analysis of the effects of estrogen replacement in the primary prevention of coronary heart disease (CHD) is discussed. During the last 4 years, there have been 4 observational studies of the use of estrogen in postmenopausal women with CHD as assessed by coronary angiography. In all of these studies, estrogen has been associated with a reduction in CHD, most strikingly in a study of survival over 10 years. However, there is an overwhelming need for a randomised controlled trial of estrogen for secondary prevention. The role of estrogen in the treatment of type II hyperlipoproteinaemia has been recognised, and a study describing its effect is discussed. Again, there is need for data from well controlled clinical trials to clearly establish the benefits of estrogen therapy. A further aspect for investigation is a study of the non-lipoprotein-mediated effects of estrogen, particularly those on vasomotion. Finally, the intriguing effects of both androgenic and estrogenic steroids on Lp(a) are discussed.