Equivocal results of the psychophysical effects of music have been explained in part by the insensitivity of researchers to important personal and situational variables when selecting music. The aim of the present study was to operationalize a conceptual framework for the prediction of psychophysical responses to music into a music rating inventory to assess the motivational qualities of music in exercise and sport environments. An initial item pool was developed and administered to 334 aerobics instructors. Exploratory factor analysis produced a 13-item, four-factor structure (association, musicality, cultural impact and rhythm response), which accounted for 59.2% of the variance. This model demonstrated acceptable fit indices when tested using confirmatory factor analysis on 314 exercise-to-music participants, and was better than an alternative two-factor model. When cross-validated using multisample confirmatory factor analysis, the model also showed an acceptable fit overall, although some invariance in the rhythm response factor was evident that can be attributed to the exclusive use of synchronous music by aerobics instructors. The Brunel Music Rating Inventory appears to be a valid and reliable tool for both researchers and practitioners to assess the motivational qualities of music in exercise and sport environments.