Background: The efficacy and safety of rituximab-based chemotherapy (R-chemo), the standard regimen for patients with diffuse large B-cell lymphoma (DLBCL), which is more common in Asia than in Western countries, are well confirmed in randomized controlled trials (RCTs). However, the safety and effectiveness of R-chemo in patients who are largely excluded from RCTs have not been well characterized. This real-world study investigated the safety and effectiveness of R-chemo as first-line treatment in Chinese patients with DLBCL. Methods: Treatment-naive DLBCL patients who were CD20 positive and eligible to receive R-chemo were enrolled with no specific exclusion criteria. Data collected at baseline included age, gender, disease stage, international prognostic index (IPI), B symptoms, extranodal involvement, performance status, and medical history. In the present study, data on safety, treatment effectiveness, and HBV infection management were collected 120 days after the last R-chemo administration. Results: Overall, R-chemo was well tolerated. The safety profile of R-chemo in patients with a history of heart or liver disease was well described without any additional unexpected safety concerns. The overall response rate (ORR) in the Chinese patients from this study was 94.2 % (complete response [CR], 55.0 %; CR unconfirmed [CRu] 18.2 %; and partial response [PR], 20.9 %). Compared to patients with no history of disease, the CR and PR rates of patients with a history of heart or liver disease were lower and higher, respectively; this tendency could be in part explained by treatment interruptions in patients with heart or liver diseases. HBsAg positivity and a maximum tumor diameter of >= 7.5 cm negatively correlated with CR + CRu, whereas age and HBsAg positivity negatively correlated with CR. Conclusions: This study further validated the safety and effectiveness of R-chemo in Chinese patients with DLBCL. Patients with a history of heart or liver disease may further benefit from R-chemo if preventive measures are taken to reduce hepatic and cardiovascular toxicity. In addition to IPI and tumor diameter, HBsAg positivity could also be a poor prognostic factor for CR in Chinese patients with DLBCL.