Objective: To describe the clinical outcomes of the Schizophrenia Outpatients Health Outcomes (SOHO) study in Argentina. Methods: naturalistic, observational, prospective and 3-year study that compared outpatients who started or changed to oral olanzapine or to any other antipsychotic (other AP). The effectiveness was measured using the Global Clinical Impression Schizophrenia Scale. Other effectiveness measures and emergent adverse events were recorded. Results: Argentina enrolled 186 patients on Olanzapine and 175 on other APs. Patients on olanzapine improved more and faster than patients in Other AP group with a statistical difference at the first and second year. Rates of clinical response were statistically greater on olanzapine vs other AP (92.4, 75.4%, respectively, p = 0.0001) and rates of relapse were similar between groups (25.9, 28%, respectively, p = 0.7436). Rates of extrapyramidal symptoms and tardive dyskinesia were statistically lower in the olanzapine group and weight gain was statistically greater during the first but not at the third year. More patients discontinued their prescribed antipsychotic due to lack of or incomplete response than due to intolerability. Conclusions: these results support the observations of faster and greater clinical improvement with olanzapine than other AP in real-world settings. A greater proportion of patients in the olanzapine group gained weight ≥ 7% from baseline to the first year and second years without statistical difference. At the third year a greater proportion of patients in other AP group gained weight ≥ 7% from baseline without statistical difference vs olanzapine. Some limitations in the design and heterogeneity of the other AP group and the nature of observational studies must be taken in account to interpret these results. ©INNN, 2009.