Among a cross-sectional sample (stratified by weight and age after birth) of 226 uncomplicated term newborns from the delivery and postnatal wards of a busy government maternity hospital in Kathmandu, the period prevalence of hypoglycaemia (corrected blood glucose of < 2.6 mmol/l) during the first 50 hours after birth was 38 per cent. (This compares with a reported prevalence rate of 12 per cent from studies of uncomplicated term newborns in the UK.) Hypothermia, young maternal age, low birth weight and early sampling after birth were independent risk factors for hypoglycaemia. Of 31 infants studied longitudinally during the same period, 27 (87 per cent) had at least one blood glucose measurement of < 2.6 mmol/l and 25 (81 per cent) a rectal temperature of < 35.5 degrees C. Fourteen infants (44 per cent) had three or more episodes of hypoglycaemia and seven infants (22 per cent) had three or more episodes of hypothermia. Hypoglycaemia is a common, preventable and neglected problem in many maternity hospitals in developing countries. Simple low-cost measures to reduce the incidence of hypoglycaemia may have a major impact on early infant mortality and neurodevelopmental sequelae of perinatal origin.