This study aims to understand the relationship between neighbourhood design and physical activity and examines New Urbanism's ability to support neighbourhood walkability. The walkability of two neighbourhoods in the City of Guelph is compared: one neighbourhood designed based on the principles of New Urbanism; the other designed as a conventional suburban neighbourhood. A modified version of the Neighbourhood Environment Walkability Scale survey was used to compare residents' travel behaviour and perceptions of neighbourhood walkability. Results indicate that residents living in the New Urbanist neighbourhood are physically more active than those living in the more conventional suburb and the residents of the New Urbanist neighbourhood perceive their neighbourhood as being more walkable than do the residents living in the conventional suburb. This research has the potential to inform planning policies and design strategies to improve neighbourhood walkability and the health of urban residents.