Glomerulonephritis is a common renal disorder, and a leading cause of end-stage renal disease. Glomerulonephritis can present in protean ways, with general features including proteinuria, hematuria, renal failure, and hypertension. Recent advances in our knowledge of glomerulonephritis have indicated that in many cases early therapeutic intervention can lead to improvement in renal function, long-term preservation of renal function, or slowing of the progression to end-stage renal failure. The goal of this review is to describe the method of evaluation of glomerulonephritis, stress the importance of general measures to preserve renal function or slow the rate of progression of disease, and finally to familiarize the reader with distinct categories of disease and their treatment.