In adult patients with growth hormone deficiency, the fatty acid composition of abdominal and gluteal fat tissues was determined prior to and at several time points after administration of recombinant human growth hormone. Values obtained before growth hormone treatment were not different from those seen in a normal population. However, as in healthy individuals, significant differences were found in the composition of the fat sampled at the different sites. Administration of growth hormone had no effect on the composition. It is concluded that a change in fatty acid composition of fat tissue is unlikely to be a factor contributing to the reported increased cardiovascular mortality in hypopituitarism and that treatment with recombinant human growth hormone has no effect on that potential cardiovascular risk factor.