Peritoneal transport rates, a critical determinant of peritoneal dialysis efficiency, vary widely among patients and may be easily categorized by standardized peritoneal equilibration test. Measurements of creatinine and glucose transfer are particularly useful in selecting optimal dialysis prescription. Patients with high-average peritoneal solute transport do well on standard CAPD even after losing residual renal function. Patients with high peritoneal solute transfer rates are likely to have inadequate ultrafiltration on standard CAPD. These patients do much better on dialysis regimens with short-dwell exchanges, such as nightly peritoneal dialysis or daytime ambulatory peritoneal dialysis. Patients with low-average and particularly with low peritoneal transport rates are likely to develop symptoms and signs of inadequate dialysis on standard CAPD as residual renal function becomes negligible, and may require high-dose peritoneal dialysis prescriptions.