The Joint Commission International (JCI) is responsible for upholding standards in healthcare and organizations in compliance receive accreditation. JCI requires quality improvement on patient safety goals, but requirements may prolong the total procedure/surgery time and reduce efficiency. Here, we evaluate the impact of JCI requirements on time periods in the operating room. We included patients who received elective and emergency surgeries under general anesthesia at Juntendo University Hospital between December 2014 and June 2016. Patients were classified as before and after JCI accreditation on December 12, 2015. The primary outcome was total procedure/surgery time. Secondary outcomes include five time periods comprising the total procedure/surgery time: pre-anesthesia time, anesthesia induction time, procedure/surgery time, anesthesia awareness time and post-anesthesia time. We compared these time periods between patients before and after JCI accreditation and patients were matched for age, sex and the specific type of surgery. Although total procedure/surgery time did not change significantly, pre-anesthesia time significantly increased (8.2 ± 6.9 minutes vs. 8.5 ± 6.9 minutes, before vs. after JCI, respectively, p = 0.028) and anesthesia induction time significantly decreased (34.4 ± 16.1 minutes vs. 33.6 ± 15.4 minutes, before vs. after JCI, respectively, p = 0.037) after JCI accreditation. Other secondary study outcomes did not change significantly. Quality improvement initiatives associated with time periods in the operating room can be achieved without undermining efficiency.