Objective: To investigate the cumulative effect of antipsychotics at different dosages on mortality in patients with schizophrenia. Methods: We analyzed data from the Korean National Health Insurance System−National Sample Cohort covering the 2002−2013 period. We used Cox regression analysis to calculate hazard ratios for mortality risks according to cumulative antipsychotic exposure levels (low, moderate, and high). Results: Our analyses revealed no significant association between antipsychotic exposure and mortality (either all-cause or cause-specific) in patients with schizophrenia. Conclusion: Our results imply that the excess mortality of patients with schizophrenia is attributable to factors other than antipsychotic usage.