An observational study was conducted to investigate the computer activity of children in a preschool classroom. Thirty-nine 3- to 5-year-old children were observed using a computer over nine weeks during a daily one-hour free play period. Different types of computer programs were available. During one half of the sessions, an adult knowledgeable about computers was available to the children for aid and support; during the remaining sessions, the teacher was not available. The children's physical and verbal behavior while using the computer was observed and recorded. Overall, the children enjoyed using the computer and preferred to use it with the teacher or a peer rather than alone. Additionally, children's activity at the computer was not significantly altered by the presence of the teacher. The observations indicated that preschool children can work effectively and cooperatively at a computer with minimal teacher supervision and that the computer does not appear to attract children to the detriment of other areas of social and cognitive development. Relatively few age or sex differences were reported. In terms of ability, more expert children were found to work at the computer more often than less expert children and also to work more efficiently. The less expert children tended to work for longer periods of time than the experts. The more expert children also used a greater variety of programs. (Author/BB) (Author/BB)