The aim of this research was to test the continuum of behavioural regulation, as outlined by Deci and Ryan (1990), in the exercise domain. A Behavioural Regulation in Exercise Questionnaire (BREQ) was developed to measure external, introjected, identified, intrinsic and amotivated forms of regulation for exercise behaviour. 298 sports centre attendees completed the questionnaire. Confirmatory factor analysis supported the existence of this gradient of autonomy in exercise behaviour regulation but high levels of skewness in the amotivation items indicated that amotivated regulation was not relevant for this sample. A four factor model with amotivation eliminated demonstrated acceptable discriminant validity and internal consistency. A second study confirmed the factor structure and internal consistency of the measure. Multisample analysis established factorial invariance across gender. Subscale intercorrelations approximated a simplex pattern, characteristic of an underlying continuum. The BREQ may allow finer analysis of the motivational forces at play in exercise adoption and maintenance situations.