The paper is based on results of a comprehensive examination of 386 children in institutions for orphans and children without parental care including an analysis of registration forms 030/1 12 - 1/u - 2000. The children’s morbidity and disability rates have been studied. Correlations between classes of diseases have been identified. Cluster and discriminative analyses allowed to divide the children into 5 groups according to the morbidity rates and health parameters. A mathematical model has been designed which allowed to refer the children to one of 5 selected groups according to the children’s diseases and a number of other characteristics. The obtained results have substantiated medical treatment and preventive work with children in orphanages.