Aim: We aimed to evaluate the frequency of catheter-related internal jugular vein (IJV) thrombosis, associated factors, and the anatomical variations of IJV in hemodialysis patients. Material and methods: Hemodialysis patients were evaluated with B-mode ultrasonography (USG). Participants in the prospective group were evaluated using USG prior to catheter insertion, 10 days after catheter insertion, at the time of catheter removal, and 15 days after removal. Results: The rate of thrombosis was increased correlated with the number of catheter insertions. These rates were 14%, 15%, and 47% in those undergoing catheter insertion once, twice, and three times, respectively (P < .05). The anatomical variations of IJV were 21% in the retrospective cases. No significant relationship was found between anatomical variations and thrombosis and between some biochemical parameters and thrombosis. Conclusion: Catheter-related IJV thrombosis is frequent in hemodialysis patients. Long catheter remaining time and repeated catheterization increase the thrombosis rate.