Few randomized clinical trials (RCTs) have been performed in patients with Churg-Strauss syndrome. Therefore, it is recommended to treat patients with this syndrome in accordance with the current practice guidelines for therapy for patients with ANCA-associated vasculitis. Standard therapy is prednisolone in combination with cyclophosphamide. Cyclophosphamide is stopped 3-6 months after diagnosis and subsequently azathioprine is started. Recently, it was demonstrated in two RCTs that B cell depletion by rituximab can be used as therapy for moderate to severe ANCA-associated vasculitis. Remission rates and adverse events were comparable with those of treatment with cyclophosphamide. It is pivotal to start therapy in patients with Churg-Strauss syndrome as soon as possible after the diagnosis is made.