This study was performed to determine the activity of adding continuous infusion (CI) of 5-fluorouracil (5-FU) to gemcitabine (GEM) vs GEM alone in advanced pancreatic cancer (APC). In all, 94 chemo-naïve patients with APC were randomised to receive GEM alone (arm A: 1000 mg m(-2) per week for 7 weeks followed by a 2 week rest period, then weekly for 3 consecutive weeks out of every 4 weeks) or in combination with CI 5-FU (arm B: CI 5-FU 200 mg m(-2) day(-1) for 6 weeks followed by a 2 week rest period, then for 3 weeks every 4 weeks). Overall response rate (RR) was the primary end point and criteria for decision were planned according to the Simon's optimal two-stage design. The overall RR was 8% (arm A) and 11% (arm B) (95% confidence interval: 0.5-16% and 2-22%), respectively, and stable disease was 29 and 28%. The median duration of RR was 34 weeks (range 25-101 weeks) for GEM and 26 weeks (range 16-46 weeks) for the combination. The median progression-free survival (PFS) was 14 weeks (range 2-65 weeks) and 18 weeks (range 4-51 weeks), respectively. The median overall survival (OS) was 31 weeks (range 1-101 weeks) and 30 weeks (1-101 weeks). Toxicity was mild in both arms. This study does not show promising activity in terms of RR, PFS and OS for the double combination arm in APC.