A prospective study of acute nephritis in children was conducted at the Universiti Sains Malaysia Hospital, Kubang Kerian between July 1987 and June 1988. One hundred and twenty four children were admitted with acute glomerulonephritis. The aim of the study was to determine the clinical pattern of the nephritis as well as its aetiology. The majority of our patients came from the lower socio-economic group and 54% of the families had incomes below the poverty line. Preceding skin infection was much more common than throat infection. The children showed a high incidence of complications: severe hypertension (43.6%), hypertensive encephalopathy (11.3%), clinical pulmonary oedema (36.3%), severe azotaemia (10.5%), and prolonged gross haematuria (13.7%). By using immunologic indices such as ASOT, anti-DNase B and complement 3, it was concluded that 121 of the 124 patients had post-streptococcal nephritis.