OBJECTIVES: Schizophrenia is a major psychotic disorder that has devastating effects on the lives of patients and their caregivers. Poor adherence to antipsychotic treatment is a well-recognized challenge among patients with schizophrenia and is associated with increased morbidity and consumption of health care resources. Implementation of innovative strategies to enhance adherence is needed. To evaluate the effect of daily Short Message Service (SMS) reminders on patients’ adherence to antipsychotic treatment in schizophrenia. METHODS: A multicenter, randomized, open-label, controlled trial. The study included clinically stabilized schizophrenic outpatients with adherence problems (at least one affirmative answer of Morisky-Green questionnaire -MAQ). Participants were randomized to receive a daily SMS reminder on their cell phone to take their medication in the following 3 months or current standard of care. The SMS reminder was sent daily at 10 a.m. or 2 p.m. according to participants´preferences. The primary endpoint was the absolute difference in mean adherence rate between the two groups after 3 months using MAQ. RESULTS: A total of 254 patients were analysed, 66.5% men. Mean age: 39.7 years (SD=11.03). Baseline socio-demographic and clinical characteristics were similar between the two groups. No significant differences in baseline mean MAQ score were observed between groups (2.23, SD=0.94 and 2.23, SD=0.85, respectively). At month 3, mean MAQ score in the intervention group was 1.2 and 1.53 in the control group. The absolute difference in mean adherence rate between groups was -0.33 (95%CI -0.62, -0.03; p=0.03). Largest change from baseline was observed in question 4 of the questionnaire “When you feel better, do you sometimes stop taking your medicine?” (percentage of affirmative answers in the SMS group vs control was 45% and 59%, respectively, p=0.02). CONCLUSIONS: SMS reminders may help many patients become sufficiently adherent to their antipsychotic medication in addition to standard interventions for schizophrenia control.