OBJECTIVE We evaluated the efficacy and safety of long-acting risperidone for 48-week period in Korean patients. METHODS This was a non-randomized, open-label, single-centered, 48-week study. Each of the participants visited the hospital every 2 weeks, and injections were given at each visit. Complete evaluations were done on five occasions (baseline, 12, 24, 36, 48 weeks). We used Clinical Global Impression, Positive and Negative Syndrome Scale, Global Assessment of Functioning, Subjective Well-being under Neuroleptic treatment scale and Short-form-36 health survey. Drug attitude inventory and Drug Induced Extra-Pyramidal Symptoms Scale were also used. RESULTS Forty patients were enrolled, and twenty-five patients completed this study. The therapeutic response rate was 36.1% in LOCF and 48% in completer's analysis. Scores on CGI, PANSS subscales and total were significantly decreased over 48-week period. Scores on other assessments did not show any significant changes over the period. At weeks 48, there was no significant difference in the changes of scores from baseline on self-rated assessments between the clinical improvement and non-improvement groups. CONCLUSIONS Our study showed significant improvement of investigator-rated psychiatric symptoms in long-term follow-up using long-acting risperidone. Further researches would be required to find out the effects of the psychiatric symptom improvements on overall changes in perceived functioning and well-being.