Background: Hemodialysis (HD) patients are at risk of developing trace element imbalances. Methods: The 12 trace elements Cd, Co, Cs, Cu, La, Mg, Mo, Pb, Rb, Sr, Tl and Zn were determined in the plasma (n = 52) of 6 chronic HD patients before and after HD sessions by inductively coupled plasma mass spectrometry. Plasma trace element concentrations were monitored for 6 months. Baseline data have been compared to the concentrations at the end of the observation period to identify a potential reduction or accumulation of trace elements in HD patients. Results: Plasma Cd, Co and Pb levels were about 10 times higher than in healthy adults. Concentrations of Co and Pb increased during HD sessions, whereas plasma Co and Cd increased during the study period of 6 months. Plasma Cs, Mg, Mo and Rb continuously decreased in all patients. For plasma Cu and Zn, a statistically significant rise of their plasma concentrations during HD and during the period of 6 months could be established. Concentrations of La and Tl did not change distinctly. Conclusion: This study revealed that plasma trace element concentrations in HD patients are distinctly different compared to that of healthy adults. Elements such as Cs, Mg, Mo and Rb are reduced and Cd, Co and Pb are accumulated in HD patients. Further studies are needed to elucidate the clinical impact of these trace element imbalances.