TAX and IFO are active drugs in antracycline and cisplatin (Pt) resistant breast and ovarian cancer. The objective of this study was to assess the MTD of IFO given in a 3-day c.i. preceded by a fixed dose of TAX (175mg/m 2 ) in a day hospital setting. Thirteen women with ovarian (9) and breast (4) cancer with advanced disease, pretreated with two or more chemotherapy regimens entered this study. Median age was 57 (range 33–69). All pts had previously received epidoxorubicin at a median dose of 360mg/m 2 (range 360–1260) alone or in combination with Pt or 5-fluorouracil and cyclophosphamide. All pts received a 3-hour infusion of a fixed dose of TAX through a central venous infuse port, followed by a 3-day c.i. of escalating doses of IFO (4-5-6-7 g/m 2 ) and equal doses of Mesna, every 21 days in subsequent groups of pts. G-CSF was given only for G4 neutropenia (N) lasting longer than 72h or febrile G4 N. MTD was defined as follows: any G4 N lasting longer than 7 days or neutrophyls <100/mL for more than 72h despite G-CSF, any G4 febrile N for more than 72 h, any G4 thrombocytopenia, any G3 non-hematologic toxicity, except for alopecia. Hematologic toxicity and related events were:IFO dose level (g/m 2 )456no. of pts/no. of courses6/326/172/2median courses/pts (range)5.5 (1–8)2 (1–5)1leukopenia WHO G3/4 (% of courses)16 (50)7 (411)neneutropenia WHO G3/4 (% of courses)16 (50)11 (65)neanemia WHO G3 (% of courses)1 (3)4 (24)nefever >38°C (% of courses)1 (3)3 (18)neG-CSF vials/pts (% of courses)14 (10)35 (35)nered cells transfusion (% of courses)0 (0)4 (24)neNo other non-hematologic toxicity except alopecia was seen.Responses are as follows: 2 CR, 1 PR, 1 SO, 1 PO, 1 NE, among the pts treated at the first dose level; ISO and 5 too early, at the second dose level. The MTD has not yet been reached, but the combination TAX + IFO has acceptable toxicity and activity.