Sleighton School, a private correctional center for court-committed delinquent girls near Philadelphia, began admitting boys in July 1975. The 70 students are about 75 percent black and 25 percent white. Staff is equally divided racially. Boys whose history includes sexual offenses or violence are excluded, as well as retarded or psychotic girls and boys. The average length of placement in the residential program is 9 months. Students are also accepted for a 4- to 6-week period for diagnostic evaluation. Boys and girls live in separate cottages housing 15 students, but school and recreational activities are coed. Major problems had to be addressed in the areas of staff attitudes, residents' reactions, the control of destructiveness, sexual acting-out, and drugs. The growing pains were worthwhile, however, since the program offers a healthy realistic setting for delinquent boys and girls that could not be achieved in a one-sex institution. Other institutions may avoid some of the problems Sleighton encountered in the change, but some difficulties are part of the change process, such as establishing sexual norms and working through staff resistances. Other hurdles, such as allowing boys special privileges, can be avoided. Staff training is important before the change is undertaken, but there still has to be a period of learning through experience. Current staff members should be mixed with newly hired staff to work with the boys, so that staff resistance to the boys won't be intensified by the newcomers. For effective treatment, both sexes should be represented on the staff. No references are cited.