The aim of our study was to assess the quality of hypertension detection and management at the Senaoane polyclinic for Black patients in Soweto and to determine the degree of patient compliance with antihypertensive drug treatment. We reviewed the records of 2,200 consecutive new patients who were 15 years of age or older. The blood pressures of 84% of the patients were measured at their first visit to the polyclinic. Of the patients seen initially by primary health care nurses, 98% were managed correctly according to the blood pressure management protocol that these nurses had been trained to use. Of 55 patients started on antihypertensive drug treatment at their first visit to the polyclinic, 31% did not visit the polyclinic again during the next year. Only 15 patients (27%) were compliant, i.e. they attended often enough during the following year to allow them to receive 80% or more of the necessary drugs. These 15 patients had substantial reductions in their diastolic blood pressures (mean reduction 21 mmHg). We regard poor compliance as the major factor preventing the polyclinic from reducing morbidity and mortality in hypertensives. Strategies for improving compliance need to be developed and evaluated for different poor compliance groups. These groups can be defined according to the severity of the hypertension and the pattern of poor compliance ("early drop-outs' v. "irregular attenders').