Serum neutrophil gelatinase-associated lipocalin (NGAL) represents a novel biomarker for early identification of various renal injuries. The purpose of the study was to evaluate the level of NGAL in some renal diseases with proteinuria. The study included 120 patients with proteinuria and 60 healthy subjects of matched age and sex. The following tests were performed: fasting blood glucose, serum creatinine, creatinine clearance, serum cholesterol, urinary albumin/creatinine ratio, 24-h urinary albumin, and NGAL. Abdominal sonography, fundus examination, and renal biopsy were done. The NGAL of a total of 120 patients (54 males and 66 females, mean age 44.6 ± 16.3 years) with renal diseases demonstrated a highly significant difference, being higher in patients with various renal diseases than in healthy controls (P < 0.001). This study confirms the existence of a raised circulating level of NGAL in CKD patients with proteinuria, which may be used as a sensitive marker for patients with proteinuria.