Highly active antiretroviral therapy (HAART) has had a significant impact on the natural history of human immunodeficiency virus (HIV) infection, leading to a remarkable decrease in its morbidity and mortality, but is frequently associated with clinical and metabolic complications. Fat redistribution or lipodystrophy, hypertriglyceridaemia, hypercholesterolaemia, insulin resistance and diabetes mellitus have been extensively reported in subjects treated with protease inhibitor (PI)-based antiretroviral regimens. In particular, dyslipidaemia occurs in up to 70-80% of HIV-infected individuals receiving HAART and can be associated with all the available PIs, although hypertriglyceridaemia appears to be more frequent in patients treated with ritonavir, ritonavir-saquinavir, or ritonavir-lopinavir. The potential long-term consequences of HAART-associated hyperlipidaemia are not completely understood, but an increased risk of premature coronary artery disease has been reported in young HIV-positive persons receiving PIs. Dietary changes, regular aerobic exercise and switching to a PI-sparing regimen may act favourably on dyslipidaemia. Lipid-lowering therapy is often required with statins or fibrates. The choice of hypolipidaemic drugs should take into account potential pharmacological interactions with antiretroviral agents.