Three cases of inverted urothelial papilloma are reported. In one case this lesion, commonly considered as benign, was associated with a transitional cell carcinoma. In an other case inverted papilloma presented histological features of a malignant tumor. The possibility of common etiologic factors of inverted papilloma and other urothelial tumors, explaining their association, is discussed. Considering these results, patients with inverted papilloma must be carefully followed in the same way as patients with low grade urothelial tumors.