A study of certain characteristics of school children and of the socio-economic characteristics of their families was made from the data secured from a sample population studied in the Eastern Health District of Baltimore, Maryland during the period between May, 1938 and June, 1943. The children in these families were divided into 2 groups according to their progress in school. All were between the ages 6 and 16 and all were observed for at least 2 years during the survey period. The satisfactory progress group was made up of 875 children from 437 families and the unsatis-factory group included 334 children representing 247 families. There was a slightly higher percentage of females among the satisfactory group than among the other group. Children in the unsatisfactory group tended to be somewhat older than the other children in their respective grades in satisfactory progress group. Asthma and hay fever appeared more often in the unsatisfactory progress children than in the children in the other group; 38.9 per thousand population as compared with a rate of 22.8 in the control group. Other chronic illnesses, in particular rheumatic fever, was much higher in the unsatisfactory than in the satisfactory group. Respiratory illnesses, changing residence, education of the head of the household and employment status were little different in each group. However, families whose children did satisfactory work in school had higher mean incomes, tended to own rather than to rent their homes and provided their children with "adequate" or "more than adequate"housing.