Keratinizing desquamative squamous metaplasia of the transitional epithelium occurs rarely in the upper urinary tract, especially in the ureter. It is associated in most cases with long-standing chronic inflammation but the exact pathogenesis is unknown, and the relationship to cancer has continued to be controversial. More cases should be accumulated for a better assessmnt of this lesion. Recently, we experienced a case of keratinizing desquamative squamous metaplasia in the renal pelvis, adjacent calyces and ureter following acute and chronic pyelonephritis. Herein, we are presenting our case with a review of literatures.