The development and initial psychometric evaluation of a Japanese version of the Health-Promoting Lifestyle Profile II (HPLP II) is described. The 52-item instrument was translated into Japanese and was found to be culturally relevant and reliable in a pilot study. The Japanese version was then administered to adiverse but predominantly Japanese group of 337 subjects residing in northern Japan. The Japanese version of the HPLP II was evaluated using factor analysis and reliability measurement. Six factors similar to those isolated previously during psychometric assessment of the English language version were extracted. Those six dimensions comprise the HPLP II subscales of: 1. Health responsibility, 2. Spiritual growth, 3. Physical activity, 4. Interpersonal relations, 5. Nutrition, and 6. Stress management. The alpha reliability coefficient for the total scale was 0.94 and the 2-week retest reliability was 0.91; the alpha coefficients for the subscales ranged from 0.70 to 0.87. The Japanese language version of the HPLP II appears to have sufficient validity and reliability for use by researchers who wish to describe the health-promoting components of lifestyle among the Japanese population and to explore differences and similarities in the health-promoting lifestyle of Japanese and American subjects or those of other ethnic groups. Further evaluations of measurement with different populations appears warranted. This instrument will enable researchers to investigate patterns and determinants of health-promoting lifestyle, as well as the effects of interventions to alter the lifestyle.