In 84 patients with advanced ovarian cancer, the measured 24-hr urinary creatinine clearance and a calculated creatinine clearance were compared prior to cis-platinum-based chemotherapy. The overall correlation between the two methods was excellent, using Pearson's coefficient of correlation test, r = 0.508 and P less than 0.000001. In a subset of 59 patients with adequate 24-hr urine collections, analysis showed a correlation of r = 0.526 and P = 0.000018. Furthermore, in this group of patients using a creatinine clearance of 45 ml/min as a threshold for dose adjustment, there was only a 3.3% error in accepting the calculated creatinine clearance for the measured creatinine clearance. In summary, in patients with advanced ovarian cancer, even in the postoperative state, an evaluation of renal function with a calculated creatinine clearance prior to chemotherapy is sufficient.