The rationale of this study is based on the fact that, both proteinuria and elevated asymmetric dimethyl arginine (ADMA) levels have been linked to the progression of vascular disease. Currently, there is not enough knowledge about any association between the levels of proteinuria and ADMA levels. Seventy-eight non-diabetic patients (42 men, 36 women, mean age of 26.1+/-5.2 years) with proteinuria having normal glomerular filtration rate were enrolled along with 38 healthy subjects (20 men, 18 women, mean age of 26.9+/-5.9 years). Proteinuria was below 3.5 g/day in 40 patients and above 3.5 g/day in 38 patients. Both groups had similar age, gender, and body mass index distributions. Serum ADMA, symmetric dimethyl arginine (SDMA), immunoreactive insulin, and high sensitivity C reactive protein (hsCRP) levels were measured. Insulin resistance was determined by homeostasis model assessment (HOMA). Serum ADMA, SDMA, insulin, hsCRP levels, and HOMA indexes were significantly higher in patients than in healthy control subjects. The above parameters were higher in the nephrotic range proteinuria group when compared to patients having protein levels below 3.5 g/day. There were significant correlations between the levels of proteinuria and the above parameters. According to the regression analysis, levels of proteinuria and hsCRP were significant determinants of serum ADMA levels. Our results indicate that, independent of other risk factors, ADMA is directly associated with proteinuria. Further studies are recommended to find out whether elevated ADMA levels are implicated in the high cardiovascular risk of proteinuric nephropathies.