The purpose of this research was to develop a psychometrically sound measure of athlete burnout. In Study 1, exploratory factor analysis revealed burn-out dimensions reflective of emotional/physical exhaustion, reduced sense of swimming accomplishment, and swimming devaluation. In two subsequent studies, the psychometric properties of a refined version of this measure were examined. Independent samples of senior age-group swimmers and college athletes from a variety of sports completed a questionnaire that tapped the three burnout dimensions as well as stress- and motivation-related variables. Confirmatory factor analysis and alternative model testing supported the specified three-factor burnout model. In support of construct validity, the burnout subscales correlated positively with stress, trait anxiety, and amotivation, and correlated negatively with coping, social support, enjoyment, commitment, and intrinsic motivation indices across the two studies.