Postinfectious glomerulonephritis is an immunologic response of the kidney to infection, commonly triggered by streptococci, although many other organisms can cause the condition. In recent decades, the prevalence of postinfectious glomerulonephritis has tended to decline in most industrialized countries, but high rates persist in some developing communities. Nowadays, patients in developed countries are usually adult and male, and those with comorbidities such as diabetes and alcoholism are at increased risk of developing the disease. The acute presentation ranges from nephritic syndrome to asymptomatic glomerulonephritis. The exact pathophysiology of postinfectious glomerulonephritis is still unknown; however, several possible pathologic antigens are under investigation. The majority of children and patients with the epidemic form of postinfectious glomerulonephritis have an excellent prognosis, which contrasts with the poor long-term outcome of sporadic cases. Therapy is largely supportive unless renal function fails to recover after eradication of the causative organism. This Review focuses on acute postinfectious glomerulonephritis, and covers its epidemiology, presentation, pathology, pathogenesis, treatment and outcomes.