Teaching style has been a popular concept for many years. Teaching style refers to the distinct qualities displayed by a teacher that are persistent from situation to situation regardless of the content. The Principles of Adult Learning Scale (PALS) has been used extensively in the West for measuring teaching style in relationship to the adult education literature, but no version has been available for use in Japan. Therefore, this research used PALS as the foundation for creating a new instrument to measure teaching style in Japan. Following a rigorous translation process, data were collected from a national sample of 1,111 nursing educators. Factor analysis and correlation were used to establish the construct and content validity of the new instrument. Reliability was established with Cronbach's alpha. The new 30-item instrument was named the Teaching Style Assessment Scale and is available in both Japanese and English for use either for personal self assessment or for research purposes.