Background & objectives: Biapenem is a newly developed carbapenem to treat moderate and severe bacterial infections. This multicenter, randomized, parallel-controlled clinical trial was conducted to compare the clinical efficacy, bacterial eradication rates and safety of biapenem and meropenem in the treatment of bacterial lower respiratory tract infections and urinary tract infections (UTIs) at nine centres in China. Methods: Patients diagnosed with bacterial lower respiratory tract infections or UTIs were randomly assigned to receive either biapenem (300 mg every 12 h) or meropenem (500 mg every 8 h) by intravenous infusion for 7 to 14 days according to their disease severity. The overall clinical efficacy, bacterial eradication rates and drug-related adverse reactions of biapenem and meropenem were analyzed. Results: A total of 272 enrolled cases were included in the intent-to-treat (ITT) analysis and safety analysis. There were no differences in demographics and baseline medical characteristics between biapenem group and meropenem group. The overall clinical efficacies of biapenem and meropenem were not significantly different, 94.70 per cent (125/132) vs. 93.94 per cent (124/132). The overall bacterial eradication rates of biapenem and meropenem showed no significant difference, 96.39 per cent (80/83) vs. 93.75 per cent (75/80). Drug-related adverse reactions were comparable in biapenem and meropenem groups with the incidence of 11.76 per cent (16/136) and 15.44 per cent (21/136), respectively. The most common symptoms of biapenem-related adverse reactions were rash (2.2%) and gastrointestinal distress (1.5%). Interpretation & conclusions: Biapenem was non-inferior to meropenem and was well-tolerated in the treatment of moderate and severe lower respiratory tract infections and UTIs.