Healthism is both an ideological and a regulative discourse that manifests as a tendency to conceive health as a product of individual choice. Healthism represents a collection of taken-for-granted assumptions, positioned at the intersection of morality, blame and health, that can lead to a privileging of 'healthy' and 'productive' individuals. It is argued that healthism is a key issue for physical educators and a significant focus for research. The validation of a scale -- the Attitude Towards Healthism Scale (ATHS) -- that seeks to quantify pre-service physical education teachers' attitudes towards healthism is described. Participants were 201 pre-service teachers undertaking a Bachelor of Education degree in Australia. The factor structure of the initial 17-item scale was determined using an exploratory factor analysis followed by Rasch modelling and, lastly, confirmatory factor analysis. Initial exploratory factor analysis supported a unidimensional measure of healthism. Further Rasch modelling suggested that a refined 15-item ATHS scale functioned more effectively as two sub-scales that combined to provide a valid and reliable method of measuring the ideology of healthism. It is suggested that the ATHS will enable teacher educators and PSTs to discuss healthism with reference to attitudinal data, and examine how views change over time.