Objective: To evaluate students’ performance and attitude after implementing DOS to the 5th year medical students.

Material and Method: DOS was introduced for the whole class of the 5th year medical students throughout the year at out-patient setting department of Medicine, Siriraj Hospital in 2012. DOS sessions were provided during the first few patients’ encounters. Students’ performances at out-patients clinics were rated for other 8 subsequence sessions. The average score were compared to the 5th year medical students in 2011 (Conventional technique, CT).

Results: Two hundred and forty six students were supervised in DOS group. The mean score of students who received DOS was significantly higher than CT group with the score of 8.2 compared to 7.9, respectively (p<0.001). With respect to students’ satisfaction, 75% of students rated DOS as a learning method with high to very high benefit.

Conclusion: DOS method is feasible to implement and could improve student’s performance with good satisfaction from medical students.

Keyword: Direct observation, Clinical skills, Medical students