Expedient antimicrobial treatment of group A beta-hemolytic streptococcal tonsillopharyngitis prevents suppurative complications and rheumatic fever; however, timely therapy does not prevent acute poststreptococcal glomerulonephritis. Acute poststreptococcal glomerulonephritis is the most common form of postinfectious glomerulonephritis and a leading cause of acute and chronic renal failure in childhood. This article discusses clinical presentation, diagnostic workup, treatment, and prevention of poststreptococcal glomerulonephritis in adults and children in the primary care setting.