Objective To evaluate the efficacy and safety of rituximab (RTX) in children with frequently relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS) after treatment with prednisone combined with standard doses of mycophenolate mofetil and a calcineurin inhibitor. Methods A retrospective analysis was conducted on clinical data from pediatric patients admitted to the Department of Pediatric Nephrology, Peking University First Hospital from January 1, 2014 to December 31, 2023. These patients had received prednisone plus standard doses of mycophenolate mofetil and a calcineurin inhibitor but still presented with FRNS or SDNS. Outcomes included remission rate, relapse rate, reduction or discontinuation of steroids and oral immunosuppressants after RTX treatment, and adverse events following RTX. Results Eighteen patients were enrolled, receiving 63 courses of RTX treatment. None presented with FRNS or SDNS after RTX treatment. Among them, 11 patients experienced no relapse from the first RTX dose to the last follow-up. After RTX administration, the duration of use of all immunosuppressants and the relapse frequency were significantly reduced (P<0.05). Most RTX-related adverse events were mild. Conclusions RTX demonstrates good efficacy and safety in children with FRNS or SDNS after treatment with three immunosuppressive agents.