Early response criteria and surgical outcome were evaluated in patients with advanced epithelial ovarian cancer treated with neoadjuvant chemotherapy. Patients with FIGO stage IIIC or IV ovarian cancer and an ascites volume of >or=500 ml were randomly assigned to receive preoperatively 3 (A1) or 2 (A2) of 6 cycles of carboplatin and docetaxel intravenously. Response was monitored by measuring target lesions, ascites volumes and serum CA 125 levels. The primary outcome measure was the preoperative reduction of ascites volume. Secondary outcome measures were the evaluation of residual tumor and perioperative morbidity and mortality. Eighty-three patients underwent cytoreductive surgery, 40 after 3 cycles and 43 patients after 2 cycles of neoadjuvant chemotherapy. 'Optimal debulking' (<or=1 cm) was achieved in 30 (A1) and 32 patients (A2). Eight (A1) and 6 patients (A2) had a persistent ascites volume>or=500 ml. A decrease of the CA 125 level from baseline of less than 50% was observed in 7 (A1) and 9 patients (A2). Computed tomography scan results showed progressive disease in 6 patients (3 A1; 3 A2). Any amount of residual disease after cytoreductive surgery, persistent ascites, and a less pronounced decrease of CA 125 were associated with poor progression-free survival rates. In conclusion, ascites volume reduction and CA 125 decline appear to be appropriate response criteria. A treatment schedule with two preoperative cycles is a reasonable option for neoadjuvant chemotherapy in advanced ovarian cancer. High surgical standards are mandatory, even after neoadjuvant chemotherapy.