The aims of this study were to investigate the economic costs of outpatients with schizophrenia in Taiwan, and to survey factors that influence the costs. The direct costs were defined as the costs associated with psychiatric services and other medical treatment. The indirect costs were estimated using the Human Capital Method. Patients' characteristics, including sex, age, duration of education, duration of illness, frequency of hospitalization, type of antipsychotic medication, severity of extrapyramidal side effects caused by antipsychotic medication, and global functions, were used to estimate the costs. The average annual total cost was approximately US$16,576 per patient. The direct and indirect costs were 13% and 87% of the total costs, respectively. Among the direct costs, folk therapy ranked third, just behind prescription drugs and acute ward hospitalization. The productivity loss of both the patients and their caregivers was the major component of the indirect costs. The patient's age and global functions had a significantly negative relationship with the direct costs. The severity of extrapyramidal side effects, type of antipsychotic medication, and the patient's illness duration correlated positively with the indirect costs, while the patient's global function correlated negatively with the indirect costs. Overall, the indirect costs of treating schizophrenia were higher than the direct costs. Improving patients' functionality and decreasing caregivers' burden are essential to reducing costs.