Acute glomerulonephritis (AGN) manifests with abrupt onset of hematuria, facial edema, hypertension and impairment of renal function. The commonest form of AGN in developing countries is that following a beta hemolytic streptococcal infection where the glomerular injury is mediated by deposition of immune complexes. In the usual patient with moderately severe poststreptococcal AGN (PSAGN) the above-mentioned features are present However, gross or microscopic hematuria may be the only abnormality. A similar picture may occasionally be produced by a variety of infections (when GN is referred to as post-infectious and the mechanism of glomerular damage and the renal histology are similar to that in PSAGN), primary renal glomerular disorders (e.g. membranoproliferative GN, IgA nephropathy), collagen vascular diseases (systemic lupus erythematosus), systemic vasculitis (Henoch Schonlein purpura) and hereditary nephritis and some nonglomerular conditions. PSAGN may also present with one or more of its complications such as profound volume expansion with heart failure and hypertensive encephalopathy. PSAGN resolves rapidly and has an excellent prognosis. Patients with severe renal involvement and life threatening complications need expert supportive management. AGN with associated systemic features or very pronounced azotemia, nonstreptococcal AGN and unresolving GN need prompt, appropriate evaluation that often includes a renal biopsy. If extensive crescentic changes are found (crescentic GN), aggressive immunosuppression will be necessary.