The crime of arson has been of great concern to the public in recent years, but there has been little empirical research in the characteristics of arsonists and their past experiences in fire. The study hypothesized that arsonists were significantly higher in hostile personality, inferiority, lack of social support and association, more experiences in fire, and positive attitude toward fire than non-arsonists. Questionnaire has been adopted as research tool. The subjects included 165 arson inmates and 465 non-arson inmates in Taiwan's prisons. The results suggested that the hypotheses are generally supported. The characteristics of arson recidivists, influence of past experiences in fire, reliability of scales, treatment of arsonists, and direction of future research were discussed.