Behavioral observations and sociometric ratings were assessed in separate 3- and 4-year-olds child-care classes across a 2-year period. In general, correspondence between behavioral observations and sociometric ratings increased with age, and social structure showed greater cohesion in the 4-year-olds class. Gender was an organizing principle in the social structure of the 4-year-olds class and became more apparent across time in the 3-year-olds class. (HTH)