The purposes of this study are to know: the role of magnesium in diabetic nephropathy, the proportion of albuminuria in type 2 DM with hypomagnesemia and normal magnesium level, and correlation between magnesium level and albuminuria. This cross-sectional study was done in Diabetes Clinic RSCM from March to June 2014 with consecutive sampling for type 2 DM patients who had been diagnosed with diabetic nephropathy. History taking, physical exam, albumin creatinine ratio test, and A1c level were done. Thirty eight subjects included in this study were mostly more than 50 years old and had poor glycemic control (81,6%). 80% of subjects with Mg level < 1.7 mg/dl experienced albuminuria and 63.6% of subjects with Mg level ≥ 1.7 mg/dl experienced albuminuria. The coefficient correlation was 0.006, which means that there is weak correlation between blood magnesium level and albuminuria. In conclusion, no correlation between magnesium level and severity of albuminuria were found in this study.