Eosinophilic cystitis is an uncommon disease in children, and its association with chronic granulomatous disease (CGD) has been previously reported in only five patients. In all those patients the disease showed either a self-limited benign course or a rapid response to corticosteroid treatment. The authors describe a child with X-linked CGD who developed eosinophilic cystitis with a recurrent course and difficult therapeutic management. The authors also discuss the pathogenesis of granuloma formation in CGD and review the literature for current therapies for these complications.