To identify predictors of outcome of acute partial hospital (PH) treatment, patients admitted during a 15-month period were studied. Outcomes were change in the Behavior and Symptom Identification Scale and readmission within 30 days. Predictors were clinical and demographic variables obtained on all patients. Most patients (92%) improved during acute PH treatment, only 5% were readmitted, and average changes were moderate to large. However, many patients still had significant symptoms and behavioral problems at discharge, 56.5% missed at least 1 day, and 16.5% dropped out. Less acute improvement was associated with greater long-term impairment, worse treatment attendance, more previous treatment episodes, and fewer medication changes. Readmission was associated with less acute improvement and its predictors, and with nonattendance. In summary, acute outcome in PH was predicted by functioning more generally. Factors that affect patients' acute PH responses may also affect functioning in other areas. These findings suggest possible modifications of PH practices and programs.