Background: Several potential risk factors have been identified for diffuse large B-cell lymphoma (DLBCL); however, epidemiological studies investigating the association between these risk factors and DLBCL have yielded inconsistent results. Objectives: To investigate potential medical, lifestyle, and environmental risk factors of DLBCL in Shanghai, China through a hospital-based case-control study. Method: One-hundred-and-forty-seven newly diagnosed DLBCL patients and 294 sex- and age-matched controls were recruited from 11 hospitals in Shanghai between 2003 and 2007. A standardized structured questionnaire was used to obtain patient data on demographics, medical history, family history, lifestyle, and environmental exposures. Conditional logistic regression models were used to estimate odds ratios (ORs), with 95% confidence intervals (CIs), for risk associated with each data category. Results: History of tuberculosis (TB) infection and "living on a farm" were positively associated with DLBCL (TB: OR=3.05, 95% CI: 1.19-7.80; farm: OR=1.82, 95% CI: 1.21-2.73). In contrast, taking traditional Chinese medicine was negatively associated with DLBCL (OR=0.36, 95% CI: 0.14-0.89). No significant correlation with DLBCL risk was found for any of the other potential risk factors (p>0.05), including but not limited to hair dyes, alcohol drinking, smoking, and home/workplace renovation within one year. Conclusions: Consistent with results from previous studies in other DLBCL case populations, traditional Chinese medicine appeared to have a direct or indirect protective effect against DLBCL. However, this study also identified a possible predisposition for DLBCL in TB sufferers and farmers.