This study compared the status and adequacy of blood pressure (BP) control in 21 ESRD patients treated with HD and CAPD at different time periods. Patients were considered to be hypertensive it they were receiving antihypertensive medications during the study period. During HD, 9 of the 21 patients (43%) required antihypertensive drugs to control their hypertension; whereas, during CAPD, the number of patients taking antihypertensive drugs increased to 15 (71%) (p < 0.05). Adequate control of hypertension (systolic BP < 150 mmHg and/or diastolic BP < 90 mmHg) was achieved in 17 patients (81%) during HD compared to 11 patients (52%) during CAPD (p < 0.05). Average ultrafiltration rate was 1.28 +/- 0.1 l/day during HD and 1.30 +/- 0.2 l/day during CAPD (p = NS). Mean Kt/V during HD was 1.24 +/- 0.1; whereas, mean weekly Kt/V during CAPD was 1.81 +/- 0.2. There were no significant differences in hematocrit or usage of recombinant human erythropoietin (rHuEPo) between the two treatment modalities. However, the weekly dose of rHuEpo was higher during HD than during CAPD (p < 0.05). Mean body weight was significantly higher (p < 0.01) and serum albumin was lower (p < 0.05) during CAPD than during HD in the same group of patients. We conclude that hypertension appears to be controlled better by HD than by CAPD in ESRD patients. The gain in body weight observed with CAPD treatment may reflect an increase in total body fluid volume which may partly explain why hypertension is less adequately controlled during CAPD than during HD treatment.