['To compare treatment outcomes by starting CD4 cell counts using data from the Comprehensive International Program of Research on AIDS-South Africa trial.', 'An observational cohort study.', 'Patients presenting to primary care clinics with CD4 cell counts below 350 cells/microl were randomized to either doctor or nurse-managed HIV care and followed for at least 2 years after antiretroviral therapy (ART) initiation. Clinical and laboratory outcomes were compared by baseline CD4 cell counts.', 'Eight hundred and twelve patients were followed for a median of 27.5 months and 36% initiated ART with a CD4 cell count above 200 cells/microl. Although 10% of patients failed virologically, the risk was nearly double among those with a CD4 cell count of 200 cells/microl or less vs. above 200 cells/microl (12.2 vs. 6.8%). Twenty-one deaths occurred, with a five-fold increased risk for the low CD4 cell count group (3.7 vs. 0.7%). After adjustment, those with a CD4 cell count of 200 cells/microl had twice the risk of death/virologic failure [hazard ratio 1.9; 95% confidence interval (CI), 1.1-3.3] and twice the risk of incident tuberculosis (hazard ratio 1.90; 95% CI, 0.89-4.04) as those above 200 cells/microl. Those with either a CD4 cell count of 200 cells/microl or less (hazard ratio 2.1; 95% CI, 1.2-3.8) or a WHO IV condition (hazard ratio 2.9; 95% CI, 0.93-8.8) alone had a two-to-three-fold increased risk of death/virologic failure vs. those with neither, but those with both conditions had a four-fold increased risk (hazard ratio 3.9; 95% CI, 1.9-8.1). We observed some decreased loss to follow-up among those initiating ART at less than 200 cells/microl (hazard ratio 0.79; 95% CI, 0.50-1.25).'] Is initiating patients on antiretroviral therapy at CD4 cell counts above 200 cells/microl associated with improved treatment outcomes in South Africa?