Children infected with the type-1 human immunodeficiency virus (HIV) are at risk of nutritional deficiencies leading to an impaired polyunsaturated fatty acid (PUFA) status. The aim of the present study was to compare the PUFA composition of plasma lipid classes (total lipids, phospholipids (PL), cholesteryl esters (CE) and triglycerides) in well-growing HIV-infected children with an age-matched group of HIV-seroreverter children born to infected mothers. Eighteen HIV children, of both sexes, mean age 4.6 y, most of whom under combined antiretroviral regimen, were compared with 18 seroreverters, mean age 5.4 y, comparable for demographic, anthropometric and dietary characteristics. All children had adequate growth parameters (weight and height > 3rd percentile). The plasma fatty acid content was similar in the two groups. HIV seropositive subjects showed lower linoleic acid (LA) levels in all the plasma lipid fractions, with higher 20:3n-9 and 20:5n-3 levels in PL and CE. The plasma PL triene/tetraene ratio (marker of relative LA deficiency) related positively to the viral load and negatively to the blood CD4+ lymphocyte count. Compared to age-matched seroreverter subjects, HIV-seropositive children show a lipid fatty acid status suggestive of relative LA deficiency and increased turnover of the PUFA series.