In a 12-week crossover study we assessed the effect of tidal volume peritoneal dialysis (TVPD) on serum chemistry, patient well-being, appetite and sleep, blood pressure, and body weight period and compared it with the effect of intermittent peritoneal dialysis (IPD) on these same parameters over a similar period. We used similar volumes of dialysis solutions per exchange and session, and the exchanges were of the same duration in each session. There were 12 patients (6 males, 6 females) with a mean age of 76 years (range 61-88 years), and mean duration of peritoneal dialysis 49 months (range 20-148 months). Five patients started with TVPD and switched to IPD after 3 months; the remaining 7 patients started with IPD and switched to TVPD for the next 3 months. No differences were seen between TVPD and IPD in any of the measured parameters: body weight, appetite, sleep, and well-being by self-assessment, number of transfusions, and complications related to peritoneal dialysis. There were two episodes of peritonitis during the TVPD period and none during the IPD period. Our data indicate that TVPD and IPD are equally effective when applied over similar durations and with similar volumes of dialysis solutions in each session. The improved results with TVPD that others have reported probably can be explained by the use of higher volumes of dialysate.