Aim: Magnesium is associated with many chronic diseases, especially cardiovascular diseases. The purpose of this study is to evaluate the relationship between serum magnesium level, glomerular filtration rate (GFR) and atherogenic index of plasma (AIP). Materials and Methods: The data of 214 patients included in the study were analyzed retrospectively. Those with an estimated GFR of 60 mL/ minute/1.73 m2 and above were grouped as the “high GFR group”, and those with an estimated GFR of less than 60 mL/minute/1.73 m2 were grouped as the “low GFR group”. AIP was calculated by taking the logarithm of the ratio of serum triglyceride level to serum high-density lipoprotein level. Results: There were 72 patients in the high GFR group and 142 patients in the low GFR group. There was no difference between the groups in terms of serum magnesium level and AIP. The factors related to serum magnesium level and AIP were investigated in the whole study population. A negative correlation was found between serum magnesium level and AIP [Odds ratio (OR): -0.212]. When the factors associated with AIP were examined, AIP was found to be negatively correlated with serum magnesium level (OR: -0.189) whereas positively correlated with body mass index, systolic blood pressure and serum uric acid level (OR: 0.154; 0.276; 0.165, respectively). There was no relationship between AIP and magnesium levels and GFR. Conclusion: The inverse relationship between serum magnesium level and AIP is consistent with the literature on the relationship between hypomagnesemia and atherogenicity. The lack of a relationship between AIP and serum magnesium level and GFR may be attributed to the small number of patients.