This article provides a general overview of some of the more common or illustrative glomerular and tubulointerstitial disorders encountered in clinical practice. Disorders are grouped into those causing the nephrotic syndrome, the acute nephritic syndrome and rapidly progressive glomerulonephritis (RPGN), and chronic tubulointerstitial disease. This division is useful for narrowing the differential diagnosis and deciding on further testing and management. Elements of the past history, including detailed family, medication, and social histories, and recent symptoms and physical examination findings are as much a part of the diagnostic workup as are urinary and blood tests. An assessment of the tempo and severity of renal deterioration is critical to separate potential medical emergencies, such as RPGN, from those more indolent disorders that can be managed by the primary care physician.