The authors analyze endo- and exogenous factors responsible for infant death during the first year of life. Biological anamnesis, conditions and life style were studied in 102 families which had infants dead during the first year of life. The data were collected by interviewing mothers and analyzing primary case histories of infants. Statistical processing of the results of social hygienic study distinguished 33 significant risk factors promoting infant death. Children born from mothers at a high risk of perinatal disease and in socially defective families are at a highest risk of neonatal death. Experience gained at pediatric health center No. 39 in Nizhnii Novgorod is described as the optimal structure of a territorial pediatric health center maximally realizing the measures aimed at prevention of neonatal mortality. This health center has a special department for infants, primary prevention center, and social public health service.