Abstract: We reported a case of ANCA-associated vasculitis with pulmonary and renal involvement that was effectively treated with glucocorticoids, cyclophosphamide, and plasma exchange therapy. The patient suffered two infections during maintenance treatment with azathioprine and was later switched to ultralow-dose (100 mg) rituximab to keep the disease in remission. Individualized rituximab therapy is effective in treating ANCA-associated vasculitis, while avoiding excessive immunosuppression, and reducing the financial burden. The diagnosis and treatment of this patient may help clinicians improve their understanding of maintenance therapy for ANCA-associated vasculitis.