background/objectives: dog ownership in older adulthood has been connected with increased likelihood of meeting the physical activity guidelines. there are older dog owners, however, that do not walk their dogs. investigation utilizing the self- determination theory was used to identify differences in motivation between regular and infrequent dog-walkers, while qualitative investigation helped identify and explore factors that influence motivation (basic psychological needs). finally, meeting the advised levels of physical activity is related to improved health, so investigation into the differences was completed. method: ninety-four dog owners, aged 55 years and older, participated in the study. participants completed the breq-2, a measure of motivation, a questionnaire to measure dog-walking behaviour, the sf-36v2, a measure of health, and demographic information. t and mann-whitney u tests were used to identify differences between in motivation and health. nine regular dog-walkers participated in interviews to explore if the basic psychological needs influenced motivation to dog-walk.