PIP: In a study conducted in the 1970s, 66.7% of healthy Ugandan children living in the West Nile district tested positive for HIV infection by direct ELISA assay. But such assays frequently yield false-positive results when sera are tested from areas where parasitic infestation is common. This study attempts to determine how long the AIDS virus has been present among the Ugandan population through a re-examination of sera from the West Nile district and an examination of the sera of old people from the Kampala area. A competitive ELISA assay was used which does not have many of the drawbacks associated with direct ELISA assays. Of 71 healthy adults tested in the West Nile district, 1 tested positive for HIV infection. 15% of healthy adults in Kampala tested positive. Of 96 old people in Kampala, all of whom for various reasons were thought to have been sexually inactive for the past 5 years, none tested positive for HIV infection. The indications of this study are that AIDS is not endemic in the West Nile, and the disease is a recent arrival to Uganda. Previous suggestions that the disease originated in Uganda are incorrect.