In this study, a randomised phase II trial explored the effects of 6-h chronomodulated CPT-11 infusion in advanced colorectal cancer patients. Sixty-eight pre-treated patients were randomly assigned to CPT-11 administered at 180 mg/m2 on day 1, by 1-h infusion (Arm A) or 6-h sinusoidal infusion with peak timing at 5:00 a.m. (Arm B). All patients also received chronomodulated folinic acid/5-fluorouracil (FA/5-FU). Patients in Arm B obtained a 25.7% response rate for 7.0 months duration, a progression-free survival for 8.0 months and a median survival of 28 months. The same data in Arm A were 18.2%, 4.5, 6.0 and 18 months, respectively. No differences in drugs dose-intensity or increased toxicity with prolonged chronomodulated infusion were detected. Major grade 3-4 toxicity was diarrhoea: 10 patients in Arm A and 13 in Arm B. In conclusion, this study has shown that chronomodulated infusion of CPT-11 and FA/5-FU is safe, active and can be integrated with oxaliplatin (EORTC 05011) for the treatment of advanced colorectal cancer.