Assessment method of medical students by conducting examination is to identify the quality and quantity of their academic performance. Essay paper is one of the most common assessment tools in the Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah. Double marking is a means by which academic staff attempts to produce fair results for the students. Eighty eight medical students sat for three sets of Essay Papers of Professional I examination in March 2012. The double marking on the essay papers was done by two lecturers of each clinical department concerned for each discipline. Inter-examiner agreement and its effect on the reliability of the final score for the students were calculated by using Kappa statistics and Intra-class Correlation Coefficient (ICC). Reliability coefficient of the scores were also calculated for the different disciplines. In Part A essay paper, Cohan’s Kappa was 0.48 (p