Background and objective:  Emergency operating room after-office hours in Srinagarind hospital triaged patients into four types (true emergency, emergency, urgent, and elective cases) by operation urgency. Our aims were to evaluate waiting time for operation and associated factors.

Method: This was a prospective descriptive study. We studied in patients who receive service in emergency operating room after-office hours. Data were sought from medical record and study record. Patients were triaged into emergency condition group by surgeons. We recorded process time from request for service until finished procedure. We also recorded the obstacle.

Result: One hundred and thirty-three patients were included into study. None of true emergency cases received procedure within 15 minutes. Seventy-six percent of emergency cases received procedure within 1 hours. Eighty-six percent of urgency cases received procedure within 6 hours. And all elective cases received procedure within 24 hours. We found obstacles were insufficient operating room and personnel.

Conclusion: After-office hours emergency operating room had opportunities to improve especially in true emergency cases.  However, other  groups  required shortening waiting time. Most common obstacle were insufficient operating room and personnel.