Balkan endemic nephropathy (BEN) is a chronic tubulointerstitial renal disease of a still unknown etiology, associated with an increased frequency of urothelial carcinoma, particularly of the upper urinary tract (UUT). The aim of the study was to compare the occurrence of UUT carcinomas between Brodsko-Posavska Region (BPR) which is the region with endemic villages and the non-endemic region of Zagreb (ZG) in two six-year periods with a 20 year period separating the two, pointing out a possible difference in occurrence regarding war in Croatia (1991-1995). Comparing BPR and ZG regions we found a more then 5 times higher frequency of UUT carcinomas in BPR in the first period and more than 4.5 times higher frequency in the second period. Women in BPR were more frequently affected with UUT carcinomas.