OBJECTIVE: To compare pharmacotherapy patterns and treatment outcomes for olanzapine- versus quetiapine-treated hospitalized patients with schizophrenia. METHODS: Hospitalized olanzapine- and quetiapine-treated patients discharged with schizophrenia (ICD9: 295.xx) between 01/1999 and 09/2001 were identified using Premier's PerspectiveTM database, the largest U.S. hospital drug utilization database. Outcome measures include use of other antipsychotics, mood stabilizers, antidepressants, anxiolytics, and hypnotics; length of stay (LOS); and total treatment costs were analyzed by regressions, controlling diagnoses, illness severity, patient and institution characteristics. RESULTS: Of 9433 patients (54.8% male, mean age 41.5 years), 6699 were olanzapine-treated and 2,734 quetiapine-treated. After adjusting for confounding factors, olanzapine-treated patients used fewer psychotropic agents (-0.36, p<0.0001) and were less likely to switch to or augment with other atypical antipsychotics (odds ratio (OR)=0.71, 95% confidence interval (CI)=0.62-0.81). Olanzapine-treated patients were less likely to be treated with typical antipsychotics (OR=0.77, CI=0.70-0.85), mood-stabilizers (OR=0.84, CI=0.77-0.93), anxiolytics (OR=0.67, CI=0.60-0.74), or anti-Parkinsonian agents (OR=0.87, CI=0.79-0.96). There was no between-group difference in antidepressant or hypnotic use. Total costs for olanzapine-treated patients were lower (-$678, p<0.0001) as the result of shorter LOS (-11.4%, p<0.0001). CONCLUSIONS: Compared to quetiapine, olanzapine treatment for hospitalized patients with schizophrenia was associated with more favorable pharmacotherapy patterns, shorter LOS, and lower costs.