HIV lipodystrophy is a heterogeneous syndrome, which has yet to be objectively defined, comprising peripheral lipoatrophy, central fat accumulation and lipomata, along with hyperlipidaemia, insulin resistance and lactic acidaemia. Both nucleoside analogues and protease inhibitors are involved, but there are also host factors that probably place some patients at greater risk. The pathogenesis is increasingly understood, with evidence of interference of several regulatory proteins such as sterol regulatory enhancer binding protein-1, the proteasome, mitochondrial DNA polymerase gamma and GLUT-4. Along with the issues of cosmesis and stigmatization, a principal clinical concern that arises with lipodystrophy is a possible increased risk of accelerated atherosclerosis. A variety of therapeutic interventions, designed to limit these risks, are under evaluation, but none is conclusively shown to be of value.