Background and Objective : Accreditation Council of Graduate Medical Education (ACGME) has recommended the duty hours for residency training should not more than 80 hours per week but there is no consensus of the appropriate duty hours for interns. This study aims to  determine duty hours of interns in university hospital and hospitals in the Ministry of Public Health.

Methods: The interns who graduated from Faculty of  Medicine, Khon Kaen University in academic year 2009 were asked to complete the questionnaires after they have been worked as the intern physician more than 6 months in university hospital or  hospitals in the Ministry of Public Health (regional hospitals and general or provincial hospitals).

Results: 168 of 182 interns replied the questionnaire. The response rate was 92.3%. Most of the interns (80-90%) worked more than 80 hours per week. Interns who worked in regional hospitals and   general hospitals significantly worked in extra duty hour longer than interns who worked in university hospitals (p =0.002).  The continuation of working hours without free-day off in university, regional and general hospitals mostly were 48 + 36, 48 + 36 , 72+ 57 hours respectively. Self- reported about medical errors was 1-2 episodes in all hospitals. Most of medical errors occurred in Medicine Department.

Conclusions: Most of the interns worked more than 80 hours per week. The interns of hospitals in the Ministry of Public Health worked in extra duty hour longer than the ones who worked in university hospitals.