Abstract. Objective: Hemodialysis patients are prone to malnutrition because of diet or many uremic complications. The objective of this study is to determine whether thiamine deficiency is associated with regular dialysis patients. Methods: To determine whether thiamine deficiency is associated with regular dialysis patients, we measured thiamine in 100 patients undergoing consecutive dialysis. Results: Average thiamine levels were not low in both pre-hemodialysis (50.1 ± 75.9 ng/mL; normal range 24 - 66 ng/mL) and post-hemodialysis (56.4 ± 61.7 ng/mL). In 18 patients, post-hemodialysis levels of thiamine were lower than pre-hemodialysis levels. We divided the patients into two groups, the decrease (Δthiamine/pre thiamine < 0; - 0.13 ± 0.11) group (n = 18) and the increase (Δthiamine/pre thiamine> 0; 0.32 ± 0.21)) group (n = 82). However, there was no significance between the two groups in Kt/V or type of dialyzer. Patients were dichotomized according to median serum thiamine level in pre-hemodialysis into a high-thiamine group (≥ 35.5 ng/mL) and a low-thiamine group (< 35.4 ng/mL), and clinical characteristics were compared between the two groups. The low-thiamine value group (< 35.4 ng/ml; 26.8 ± 5.3 ng/ml) exhibited lower levels of serum aspartate aminotransferase and alanine aminotransferase than the high-thiamine value group (≥ 35.4 ng/ml; 73.5 ± 102.5 ng/ml) although there was no significance in nutritional marker, Alb, geriatric nutritional risk index , protein catabolic rate and creatinine generation rate. Conclusion: In our regular dialysis patients, excluding a few patients, we did not recognize thiamine deficiency and no significant difference in thiamine value between pre and post hemodialysis.