The tuberculosis (TB) notification rate is high and increasing in 2 communities in Cape Town, South Africa. In 2002, we conducted a prevalence survey among adults > or = 15 years of age to determine the TB prevalence rate; 15% of households in these communities were randomly sampled. All persons living in sampled households were eligible for chest radiography and sputum examination. Of the 3,483 adults who completed a questionnaire, 2,608 underwent chest radiography and sputum examination. We detected 26 bacteriologically confirmed TB cases and a prevalence of 10.0/1,000 (95% confidence interval [CI] 6.2-13.8 per 1,000). We found 18 patients with smear-positive TB, of whom 8 were new patients (3.1/1,000, 95% CI 0.9-5.1/1,000). More than half of patients with smear-positive TB (10, 56%) had previously been treated. Such patients may contribute to transmission of Mycobacterium tuberculosis and the high TB prevalence rate. Successful treatment of TB patients must be a priority.