Objective: Permanent catheters are used for vascular access in some patients undergoing hemodialysis (HD). Our aimin this study was to evaluate the risk factors of permanent catheter thrombosis and the necessity of anti-coagulant andanti-aggregation drugs.Materials and Methods: In this retrospective study, 34 patients undergoing HD, with removed internal jugulary permanentcatheters due to either thrombosis or maturation of operated arteriovenous fistulas, were included. Patients were dividedinto thrombotic and non-thrombotic, according to the catheter thrombosis status.Results: The mean age was 66.3±15.4 years, and the follow-up period was 10.9±8.5 (1-29) months. Catheter thrombosiswas found in 12 patients. Albumin and total protein levels were lower in the baseline thrombotic group (3.53±0.46 g/dLand 6.64±0.92g/dL, respectively)than in the non-thrombotic group (3.95±0.41 and 7.37±0.46g/dL, respectively).In thenon-thrombotic group, hemoglobin, hematocrit higher, and platelet count were lower at the catheter removal time compared to the catheter insertion time (hemoglobin 11.45±1.25, hematocrit 35.61±4.51, and platelet count 193.82±66.32versus hemoglobin 10.33±1.37g/dL, hematocrit 31.38±3.79% and platelet count 231.77±71.7x103/uL, respectively), but inthe thrombotic group, the ferritin levels significantly increased from 541.3±574.8ng/mL at the catheter insertion time to745.1±406.5ng/mL at the catheter removal time.Conclusion: Anti-coagulant and anti-aggregation drugs and renal failure etiology did nothave any effect on permanentcatheter thrombosis, but the albumin and total protein levels were related to it. Increased levels of ferritin and C-reactiveprotein seem to emerge as the acute phase reactants associated with thrombosis.