Eosinophilic cystitis is a low frequency disease, with less than 200 reported cases in the world. It is characterized by a bladder wall inflammation, mainly by eosinophils, with fibrosis and muscle necrosis areas. Its origin seems to be immunological, although the triggers are not well known. Several predispose factor have been described such as allergic diseases, bladder injuries, drugs, infections, etc. It affects patient of all ages, mainly adults. It presents with frecuency, haematuria and suprapubic pain. Other less frequent symptoms are disuria, urinary retention, nicturia, and enuresis. The laboratory study (urinalysis, urinalysis and haemogram) and radiology (ultrasound, intravenous pyelography, computed tomography and nuclear magnetic resonance) are non specific. The lesions observed in the cystoscopy could emulate other diseases, that why the proper diagnostic is the histological analysis. The management could be observation o antihistaminic, anti-inflammatory and corticoid treatment. In refractory cases, surgery is an alternative. In this work, two male adult cases are reported with their symptoms, studies and management.