We report the history and clinical findings in 17 patients with primary HIV infection (PHI) diagnosed in the first 6 months of 1994. 9 of these patients were infected through heterosexual contacts, 5 were women with, as the only risk factor, sexual contacts with infected men. 10 of the 17 patients were symptomatic and the diagnosis of PHI was suspected in 8 of these patients at their first medical visit. However, the laboratory investigations were incomplete since p24 Ag was only requested for one patient and this led to a delay in diagnosis. Sera collected at the time of the first medical visit were available for 4 symptomatic patients, and in all of them p24 Ag was detected in the absence of HIV specific antibodies. These data underline the frequent occurrence of HIV transmission by the heterosexual route and the need to search for both specific antibodies and p24 Ag at the time of PHI.