The objective of this study was to evaluate the clinical utility of the nursing psychoeducation program (NPE) for improving the acceptance of medication of inpatients with schizophrenia as well as their knowledge regarding their illness and the effects of medication on it. This study was a quasi-experimental study involving a convenience sample and was performed at the acute treatment units of two Japanese psychiatric hospitals. The subjects were recruited from among the inpatients being treated at the acute treatment units and were assigned to either the experimental or control group. The experimental group took part in the NPE, and the control group received the standard treatments for schizophrenia. Data were collected using structured questionnaires; i.e., the Medication Perception Scale for Patients with Schizophrenia (MPS), Drug Attitude Inventory–10 Questionnaire (DAI-10), and Knowledge of Illness and Drugs Inventory. Forty-three patients (13 men and 30 women) agreed in writing to participate in this study. During pre-/postintervention comparisons, the total MPS score, the ‘efficacy of medication’ subscale score, and the total DAI-10 score exhibited significant group × time interactions.