The ability of WHO clinical staging to predict CD4 cell counts of 200 cells/microl or less was evaluated among 1221 patients screened for antiretroviral therapy (ART). Sensitivity was 51% and specificity was 88%. The positive predictive value was 64% and the negative predictive value was 81%. Clinical criteria missed half the patients with CD4 cell counts of 200 cells/microl or less, highlighting the importance of CD4 cell measurements for the scale-up of ART provision in resource-limited settings.