Although standardized patients (SPs) have been used widely in medical education, there has been little research on SP trainers. The purpose of this study was to examine the roles SP trainers by establishing their job description and assessing the importance, frequency, and difficulty of each task element. SP trainers' responsibilities were defined and their job descriptions were developed based on a focus group interview (FGI) of 6 panels. The validity of the duties, tasks, and task elements that were elicited from the FGI was examined by the 6 panels and a medical school professor. The data were collected using a questionnaire survey from 24 SP trainers in April 2011. The questionnaire pertained to the importance, frequency, and difficulty of the duties, tasks, and task elements that were identified in SP trainers' job descriptions. The job description of SP trainers consisted of 10 duties, 25 tasks, and 76 task elements. The average level of importance of the 10 duties was 4.29; "SP training" was identified as the most important duty (4.79+/-0.41). Of the 76 task elements, "providing training regarding the scoring criteria and standardizing the scoring system" had the highest levels of importance and frequency (4.83+/-0.48, 4.08+/-1.06). "Standardizing the acting abilities of SPs" was the most difficult task element (4.50+/-0.66). By analyzing the job description of SP trainers, this study is expected to help define the roles of SP trainers and facilitate their deployment.