The aim of this study was to analyze morphometric parameters of renal arteries (longest diameter and tunica media thickness) in patients with renal cell carcinoma (RCC), to look into their relationship to tumor necrosis and to compare them with morphometric parameters recorded in a control group. We analyzed archival cases of RCC diagnosed in 2003 that also contained routinely sampled specimens of distal segments of renal artery. The control group consisted of specimens from both renal arteries obtained from 16 patients at routine autopsy during 2004-2005. Autopsy, as well as further histological analysis, did not disclose any malignant disease in the control group. Morphometric analysis of diameter and thickness of the renal artery tunica media was performed using Issa 3.1 software (Vamstek 2002, Zagreb, Croatia). The comparison of tunica media thickness showed that renal arteries from RCC cases were significantly thicker compared to distal parts of renal arteries in the control group (p=0.0002). Although renal artery samples from cases with necrotic tumor areas were thicker than those without tumor necrosis, the difference was not statistically significant. It is concluded that significantly thicker tunica media characterizes renal arteries in the group of patients with RCC when compared with the control group.