Aim The use of an immunosuppressant is recommended as a treatment for remission induction in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).However, the immunosuppressant is sometimes discontinued due to an adverse event. We sought to identify the cause and risk factors for immunosuppressant discontinuation in patients with AAV receiving remission induction treatment. Methods We retrospectively analyzed the cases of AAV patients treated in 2005-2016 with immunosuppressants to induce remission. We defined "discontinuation" as stopping, switching, or delaying immunosuppressant administration due to adverse events. We performed a multivariate analysis to identify risk factors for immunosuppressant discontinuation. Results We identified 50 patients treated with an immunosuppressant for remission induction: cyclophosphamide was used in 45 patients (90%), methotrexate in 4 (8%), and cyclosporine A in 1 patient (2%). Among them, 26 patients (52%) underwent discontinuation of the immunosuppressant. Infection and myelosuppression were the major causes of discontinuation. Multivariate Cox proportional hazards regression analysis revealed that a cumulative dose of prednisolone >= 2000 mg (hazard ratio [HR] =2.18, 95% confidence interval [CI] =1.37-3.70,P < .001), performance status of 3-4 (HR = 1.80, 95% CI = 1.07-3.03,P = .027), and oral cyclophosphamide (HR = 1.81, 95% CI = 1.11-2.97,P = .018) were independent risk factors correlated with immunosuppressant discontinuation. Conclusion Physicians should be aware of risk factors predicting immunosuppressant discontinuation when treating AAV patients with an immunosuppressant.