Twenty-four patients with progressing or recurrent ovarian carcinoma, all pretreated with cisplatin, were evaluated for response and toxicity to mitomycin C (MMC) and 5-fluorouracil (5-FU) chemotherapy. Eligible patients had histologically proven intra-abdominal disease (67% clinically measurable; 33% nonmeasurable), and 67% of them had progressed on prior platinum-based chemotherapy. WHO response criteria were adopted in patients with measurable disease while those with nonmeasurable lesions were considered as responding in case of nonevident disease and CA-125 values less than 35 U/dl for at least 6 months. All patients received at least 2 treatment courses (median 6, range 2-10), and 5 patients (21%) could be considered as responding: 4/8 (50%) with nonmeasurable and 1/16 (6%) with measurable disease. The overall median survival was 12 months, range 7-30+ (median follow-up: 29.5 months, range 28-30). Progression-free survival was significantly different in responders (15 months) versus nonresponders (3 months) (p = 0.0001). Toxicity was mainly represented by myelosuppression (grade I 29%; II 8% and III 4%). MMC and 5-FU did not show significant activity against large tumor burden, while a relatively good activity was detected in patients with minimal disease. The limited toxicity and possible schedule modifications have to be taken into account for further investigation on selected patients.