The New York State experimental prekindergarten programs are interdisciplinary endeavors whose purpose is to improve the educational opportunities of disadvantaged 3- and 4-year-olds. Because the pupil services they offer are of central importance to these programs, the social worker is an integral member of the prekindergarten staff and has many diverse functions to perform. The social worker can be assisted in the social services component of the program by pupil services aides recruited from local disadvantaged neighborhoods. Recent emphasis on parent participation in preschool programs highlights the importance of the social worker's main function: the establishment of effective relationships with parents. Some other suggested functions for a social worker are (1) to act as liaison between the program and community social agencies, (2) to participate actively in the selection and recruitment of children, (3) to coordinate the efforts of all individuals and agencies involved, and (4) to contribute information to confidential pupil records. (MH)