Patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) have high mortality despite the introduction of immunosuppressive therapy. We investigated factors associated with mortality of patients with AAV in a single Chinese cohort. A total of 398 consecutive patients with AAV diagnosed in our center were recruited. Clinical and laboratory data were collected retrospectively. The predictive values of variables associated with mortality were analyzed. During followup of a median duration 25.5 months (range 1-196 mo), 135 out of 398 patients (33.9%) died, with 83 deaths within the first 12 months after diagnosis. Independent predictors of all-cause mortality were age (p < 0.001), secondary infection (p < 0.001), pulmonary involvement of AAV (p = 0.012), and initial renal function (p = 0.001). Secondary infection was the leading cause of death (53/153, 39.3%) during the first year after diagnosis, while cardiovascular event was the leading cause of death (15/53, 28.8%) after 12 months from diagnosis. Independent predictors of secondary infection were age (p = 0.002), initial renal function (p = 0.041), lymphocyte counts in the peripheral blood (p = 0.03), and underlying pulmonary involvement of AAV (p = 0.001). Secondary infection is the overall leading cause and independent predictor of death in patients diagnosed with AAV. Cardiovascular event is a major cause of death during the late followup. Prudent monitoring should be given to patients of advancing age with renal dysfunction to reduce adverse events, especially infectious complications.