The purpose of this study was to develop a scale for the evaluation of exercise instructs’ professional competency. A total of 100 physical education students of Fu Jen Catholic University were involved. They were asked to respond to a scale containing 40 items describing exercise instructors’ professional competency. The collected data were factor analyzed. Of the several solutions extracting different numbers of factors, a six-factor solution was found to be the most meaningful. The factors were labeled “Administrative management”, “Related knowledge”, “Instructional operations”, “Working attitude”, “Documents handling”, and “Social interaction”, which accounted for 35.79%, 5.55%, 4.27%, 2.89%, 2.80% and 2.41% of the total variance, respectively. Cronbach’s alpha was calculated for each subscale. The internal consistency coefficients was .921 for the whole scale and ranged from .75 to.85. for the subscales.