The infant and early childhood mortality, its causes and associated factors were studied prospectively, in twelve Anganwadi centres, situated in urban slums of Patna from 1st January, 1987 to 31st December, 1987. A strict recording of births and deaths was done by Anganwadi workers, with monthly verifications by authors. The causes of death were established on the basis of clinical and corroborative enquiry from the parents. The birth rate was found to be 29.25, death rate 13.1, infant mortality rate 64.65/1000. Neonatal and post neonatal mortality rates were 49.42/1000 and 15.21/1000, respectively. Mortality in children between 1-3 years (11.3/1000) was higher in comparison to that of 3-6 years (9.1/1000). Low birth weight (25.52%) and perinatal infection (23.52%) were the major causes of infant mortality followed by respiratory infection (11.76) and diarrhea (8.82%). Diarrhea (37.5%), respiratory infection (15.62%) and accidents and burns (12.5%) were major killers in children between 1-6 years. Mortality in males was higher than females in infancy. Risk factors associated with infant mortality included extremes of maternal age (less than 20 and greater than 30 years), multiparity and illiterate mothers.