Authors report on two rare cases of eosinophilic cystitis, giving a review of the etiologic assumptions and pathogenetic, pathologic aspects of the disease, based on the available literary data. The course of the disease can be either acute or subacute, and is most often chronic. Relapse and progression can interchange in irregular manner, attention is therefore called to the importance of follow-ups. Resection deep into the intact--also containing muscle fibre--as well as histologic examination are considered essential as the only method of differentiation, giving precise diagnosis in the present two cases, too.