Recurrent pericarditis occurs in association with various medical conditions, but in most cases the condition appears to be idiopathic. Although high-dose steroid treatment is often effective, it may have serious side effects. Herein we describe 3 children with recurrent pericarditis who were treated at our hospital, during flares, with the interleukin-1β receptor antagonist anakinra, with immediate response. Pericarditis recurred when anakinra treatment was discontinued, and no further episodes occurred after it was resumed. Idiopathic recurrent pericarditis shares several features with autoinflammatory diseases, and anakinra has been efficacious in the treatment of the latter diseases. The findings in these patients suggest that idiopathic recurrent pericarditis may be a previously unrecognized autoinflammatory disease.