Admission, discharge, and follow-up evaluations of 110 children admitted to a child psychiatric unit (mean 14 days) showed that the children's psychological functioning improved significantly during hospitalization. Gains were not fully maintained at follow-up (1 and 6 months), but the children were still significantly less impaired after discharge than at admission. A nonsignificant difference existed between follow-up scores, indicating no loss of progress or decline in functioning from 1- to 6-month follow-up. The results are consistent with an ABA (A = no inpatient intervention, B = inpatient intervention, A = no inpatient intervention) treatment effect. They are not explained by removal from and return to an unsatisfactory home environment. Psychological functioning after admission was significantly better than after 1 to 6 months of post-discharge psychiatric services. This study offers a clinically feasible approach to evidence-based practice by documenting patient improvement during and after inpatient treatment using a simple, empirically supported assessment instrument.