Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a 25 kDa protein that plays a crucial role in the early diagnosis and monitoring of various diseases, particularly acute kidney injury (AKI) and diabetic nephropathy (DN). NGAL is highly sensitive and specific for detecting AKI, often rising within 2 hours post-injury, well before serum creatinine levels change. This makes it a valuable tool for early intervention, especially in high-risk patients such as those undergoing cardiac surgery or exposed to nephrotoxic agents. In diabetic patients, NGAL serves as an early indicator of renal tubular injury, often preceding the appearance of microalbuminuria. Studies have shown that elevated urinary NGAL levels correlate with the progression of DN, making it a promising biomarker for early detection and management. NGAL is a versatile biomarker with significant clinical utility in early diagnosis, prognosis, and monitoring of kidney-related and other systemic diseases. Its ability to provide early and accurate insights makes it a valuable tool in modern medicine.