This study assessed prescribing physicians' attitudes toward early initiation of HAART, three months after the dissemination of the first French official treatment guideline. Telephone interviews have been made in a national random sample of physicians with full- or part-time practice in hospital departments delivering care for HIV-infected patients. Questionnaires included hypothetical clinical cases. Logistic regression compared characteristics of respondents according to attitudes toward HAART. Among the 483 respondents (response rate = 87.0%), agreement was high with official recommendations to systematically initiate HAART with protease inhibitors (PIs) for patients with CD4+ cell counts < or = 300/mm3, following a diagnosis of acute primary HIV infection, or for HIV sexual risk post-exposure prophylaxis. Confronted with a case of a naive asymptomatic patient with stable 450 CD4+/mm3, 34.6% would prescribe HAART with PIs in any case, and 29.8% only if the patient has plasma viral load < or = 10,000 HIV RNA copies/ml. The remaining 35.6% would not prescribe PIs and were older, had limited activity in HIV care and expressed more interest in alternative medicines. To avoid a confusing impact of variability of clinical attitudes toward uncertainties associated with antiretroviral treatments among HIV-infected patients, shared decision-making between patient and physician should be promoted for initiation of HAART. [Authors]