The objective of this study was to apply serious leisure theory to voluntary interpreters in Taroko National Park. This study was based on the serious leisure characteristics from Stebbins (2001) and explored the relationship between leisure involvement and serious leisure characteristics of voluntary interpreters. This study investigated voluntary interpreters in Taroko National Park by a mailed questionnaire and a total of 144 valid questionnaires were received. The results showed that the 27 serious leisure characteristics were reduced into exactly 6 factors which Stebbins has suggested, including 'personal benefit derived from interpretation service', 'perseverance', 'unique ethos', 'identification', 'career development' and 'personal effort'. And this study also found that there are significant differences between serious leisure characteristics and leisure involvement. Participation frequencies and days, years of service, interpretation techniques, and owning national park related books were significantly related to different serious leisure characteristics.