Experienced runners completed a Thoughts During Running Scale (TORS) immediately after a typical training run to assess the prevalence of certain thoughts during running. The Profile of Mood States (POMS) was also completed before and after the run. Confirmatory factor analyses revealed that a five-factor model provided better fit than simpler models. Items concerning the demands of the running activity and the monitoring of body responses loaded on one "associative" factor. The four "nonassociative" factors in this model were labeled Daily Events, Interpersonal Relationships, External Surroundings, and Spiritual Reflection. Correlational analyses indicated small but significant relationships between the TDRS dimensions and changes in mood. Increases in vigor were correlated with the tendency to engage in nonassociative thought, and decreases in tension and anxiety were found among those who thought about interpersonal relationships during the run. These results supplement findings on the effects of certain thought patterns during strenuous exercise.