This research aims at testing the relevance of the personality and the medical representative (MR)'s sales performance in exploratory. In this research, as a personality measurement we used the Temperament and Character Inventory (TCI) developed by Cloninger. In recent years, the TCI has been capturing since the researches demonstrating the relevance the temperament measure and gene information was published. Significant relevance was observed between the sales performance of MR and the temperament measure in the TCI. Further more, when it divided into eight types from a temperamental combination based on the theory of Cloninger, it was demonstrated that sales performance of “passionate persons” is significantly better than that of “violent emotive person”. Based on the results that a significant difference arises in the sales performance with the combination of the temperament which is supposed is easy to be influenced of genes, the future influence and problem in a personnel management are discussed.