We report on a rare case of cystitis glandularis complicating an eosinophilic cystitis in an adult. Complaints at presentation included dysuria, haematuria and abdominal pain. Ultrasound and cystoscopy suggested a bladder tumor. Histological analysis of bladder biopsy showed the typical findings of cystitis glandularis associated with eosinophilic cystitis. The patient was treated with transurethral resection of the lesion and a combination of corticosteroids and anthistaminics for three months. He is disease-free at 24 months of follow-up.