We report two cases of severe hypertriglyceridaemia associated with human immunodeficiency virus infection and highly active antiretroviral therapy (HAART). The first patient, a 39-year-old man, developed moderate hypertriglyceridaemia (5.88 mmol/L) and hypercholesterolaemia (7.0 mmol/L) after 8 months of HAART. When his therapy was altered, triglyceride and cholesterol concentrations increased further to 15.9 and 10.9 mmol/L, respectively, after 6 weeks. The second patient, a 31-year-old man, presented with triglyceride and cholesterol concentrations of 16.2 and 5.7 mmol/L, respectively, following an 8-year history of HAART. Therapy was changed, but 1 month later the triglyceride concentration had increased to 39.4 mmol/L and the cholesterol concentration to 12.1 mmol/L. Both patients were managed by a change in HAART and the introduction of a fibric acid derivative. Although neither patient displayed any clinical symptoms associated with hypertriglyceridaemia, it is important to recognize such cases because of the associated risk of pancreatitis and coronary disease.