Health Canada has published national physical activity (PA) guidelines, which are included in their 26-page Physical Activity Guide to Healthy Active Living (CPAG). To date, the use of CPAG as a motivational instrument for PA promotion has not been evaluated. The purpose of this study was to determine whether reading CPAG 1) increased motivational antecedents to engage in regular PA, and 2) increased regular PA intention and behaviour over 1 month. Participants included 130 randomly sampled Canadian adults (18 years or older) who were randomly mailed pack ages consisting of either 1) a questionnaire and a copy of CPAG, or 2) a questionnaire. Questionnaire items pertained to participants' sociodemographics, previous PA behaviours (Godin Leisure-Time Questionnaire) and PA motivation (theory of planned behaviour). Participants were then sent a follow-up questionnaire pertaining to their PA behaviours throughout the previous month. Results revealed significant interactions between the guide condition and previous activity status on instrumental behavioural beliefs about strength activities and subjective norms about endurance activities (p < 0.05), but all other factors were not significantly different. It was concluded that among previously inactive people, receiving this guide may change some informational/motivational constructs, but key motivational antecedents (affective attitude, perceived behavioural control) and outcomes (intention, behaviour) seem unaffected.