Nephrotic syndrome is one cause of end-stage kidney disease. Because edema is a common presenting feature and hypertension and dyslipidemia are often present in nephrotic syndrome, it is important for the primary care physician to suspect this entity. Common causes in adults include diabetic nephropathy, focal segmental glomerulosclerosis, and membranous nephropathy. In adults, many primary causes are due to an underlying disease. A cause of the nephrotic syndrome should be established with serologic workup and renal consultation. Renal biopsy is necessary in those with an unknown cause to or classify disease. Treatment focuses on symptoms, complications, and the primary cause.