Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is increasingly recognized in older patients. The differences in disease presentation and outcome between older and younger patients remain controversial. We conducted the current study to analyze the characteristics of patients aged over 65 years with AAV and to compare the younger and older cohorts. We recruited 234 consecutive Chinese patients with AAV. We compared clinical and pathologic characteristics as well as outcomes between younger and older patients. Among the 234 patients with AAV, 99 were older than 65 years. Compared with the 135 younger patients, the older patients had a significantly higher proportion of positive myeloperoxidase-ANCA (94.9% vs. 80.0%, p < 0.01) and a higher proportion of microscopic polyangiitis (79.8% vs. 50.4%, chi = 11.8, p < 0.001), but had a lower proportion of Wegener granulomatosis (18.2% vs. 37.8%, p < 0.01) and renal-limited vasculitis (0% vs. 11.1%, p < 0.001).Older patients had more prevalent and severe pulmonary involvement than younger patients, including pulmonary infiltration, interstitial fibrosis, and mechanical ventilation dependence at presentation (47.5% vs. 31.9%, p < 0.05; 37.4% vs. 18.5%, p < 0.01; and 9.1% vs. 1.5%, p < 0.05, respectively). Older patients were less likely to respond to treatment (p < 0.01) and had worse survival than younger patients (p = 0.000). During follow-up, older patients had a higher risk of secondary pulmonary infection (p < 0.001), and those with pulmonary interstitial fibrosis were more likely to develop secondary pulmonary infections (p < 0.05). In conclusion, compared with younger patients, older patients with AAV had more severe and more prevalent pulmonary lesions, which might contribute to subsequent pulmonary infections after the initiation of immunosuppressive therapy. Age and pulmonary infection were independent predictors of death.