A phase I study of gemcitabine (GEM) and UFT combination chemotherapy was performed for unresectable pancreatic cancer. The regimen included UFT orally from day 1 through day 6 and from day 8 through 13, GEM intravenously on day 7 and 14, and 1 week rest as 1 course. Administration of more than 2 courses was attempted for each patient, with the same dosage levels at all 3 scheduled steps. Nine patients were enrolled in the study. Leukopenia and neutropenia of grade 3 occurred in 2 of 6 patients at level 2, and maximum tolerated dose (MTD) was considered to be 800 mg/m2 for GEM and 250 mg/m2 for UFT. Clinical effects of the patients included: 2 PR, 4 NC, and 3 PD, for a response rate of 22% (2/9 patients). Reduced CA19-9 level of less than half of that at starting time was observed in 4 of 9 (44%) patients. The recommended dose for the phase II study is GEM 800 mg/m2 and UFT 250 mg/m2 with consideration of application to outpatients and continuing courses.