Although nurse practitioners are well placed to counsel patients about getting enough exercise, little abstract is known about their attitudes and practice in this area of health promotion. The authors used a self-administered Internet-based questionnaire to explore how Canadian NPs perceive their competence in prescribing physical activity and the importance they ascribe to doing so. Participants were asked to identify factors that most commonly prompt physical activity prescription. Overall, the respondents felt fairly competent in their ability to prescribe physical activity (mean score 4.49/6.0, SD = .90) and felt that this function was important (mean score 4.82/6.0, SD = .85). Competence in prescribing physical activity and a perception that this intervention is important were both positively correlated with frequency of prescribing. The most commonly reported barrier to prescribing physical activity was a lack of time. On average, respondents prescribed physical activity to 59 per cent of their patients. The patient factors that most commonly prompted physical activity prescription were overweight or obesity, type 2 diabetes, hypertension and cardiovascular health. The lack of specific education in preventive medicine (e.g., obesity prevention, physical activity, nutrition) reported by 63 per cent of respondents points to the need for a physical activity prescription curriculum within nursing education to equip future NPs to respond to the high prevalence of physical inactivity in Canadian society.