A wide range of morphologic alterations and lipid metabolism abnormalities have been recently described in HIV-infected patients receiving a protease inhibitor-based highly active antiretroviral therapy. The hyperlipidaemia may involve up to 70-80% of HIV-positive subjects treated with a protease inhibitor-containing regimen, and it is frequently (but not always) associated with the fat redistribution syndrome or lipodystrophy. The potential clinico-pathological consequences of HIV-associated hyperlipidaemia are not completely known, but several anecdotal observations reported an increased risk of prematury coronary artery diseases in young HIV-positive individuals receiving protease inhibitors, besides peripheral atherosclerosis and acute pancreatitis. A hypolipidaemic diet and regular physical exercise may act favourably on dyslipidaemia, but pharmacological therapy becomes necessary when hyperlipidaemia is severe or pesists for a long time. The choice of hypolipidaemic drugs is problematic because of potential pharmacological interactions with antiretroviral compounds and other antimicrobial agents, associated with an increased risk of toxicity and intolerance.