Hypomagnesaemia has been reported among patients undergoing hemodialysis (HD). Recently, a possible correlation between serum magnesium (Mg) and C-reactive protein (CRP) has been stressed. This correlation has been attributed to cytokine production and oxidative stress processes. In this study we aimed to determine the relationship between serum Mg and hs-CRP levels in patients undergoing HD. This is a cross sectional study based on data collected from 58 HD patients in the Sahraee Center of Shiraz, Iran in 2007. Data were analyzed by SPSS.15, using Mann-Whitney test, Pair t-test, and Pearson's correlation coefficient. A p value of less than 0.05 was considered significant. The present study included 58 HD patients (33 M and 25 F). The mean age of our patients was 51 +/- 17.5 years old. At the start of HD, 39% of our patients had hypomagnesaemia and 60% had high hs-CRP, and 31% had both. There was a significant negative correlation between serum Mg and serum hs-CRP (p < 0.04). Also, in those who had hypomagnesaemia, hs-CRP was higher (p < 0.02). The results of this research support our hypothesis that hypomagnesaemia in pre-dialysis patients is a risk factor for sub-clinical inflammation due to hs-CRP elevation, although further studies are clearly required.