Abstract Objective Fludarabine, cyclophosphamide and rituximab (FCR) is the standard regimen for fit patients with untreated CD20-positive chronic lymphocytic leukemia (CLL). However, this combination is unavailable in Japan because rituximab is not approved for CLL. We investigated the efficacy and safety of FCR in this single-arm, multicenter study designed as a bridging study to the CLL8 study by the German CLL Study Group. Methods The study enrolled previously untreated patients with CLL of Binet stage B or C with active disease. Patients with a Cumulative Illness Rating Scale score of ≤6 and creatinine clearance of ≥70 ml/min were eligible. Patients received 6 cycles of FCR every 28 days and were followed for up to 1 year. Results Seven patients were enrolled. The best overall response rate according to the 1996 NCI-WG Guidelines, the primary endpoint of the study, was 71.4% (95% confidence interval, 29.0–96.3%), with one patient achieving complete response. No deaths or progression occurred during follow-up. The main adverse event was hematotoxicity. CD4-positive T-cell count decreased in all patients; most patients showed no reduction in serum immunoglobulin G. Conclusion Although the number of patients was limited, FCR appears to be effective with manageable toxicity for treatment-naïve fit Japanese patients with CD20-positive CLL. Clinical trial number JapicCTI-132285. FCR regimen was feasible with manageable toxicity for treatment-naïve fit Japanese patients with CD20-positive CLL, and the efficacy was in line with that seen in the CLL8 study.