Purpose: Increased core (brain or body) temperature that accompanies exercise has been posited to play an influential role in affective responses to exercise. However, findings in support of this hypothesis have been equivocal, and most of the performed studies have been done in relation to anxiety. The aim of the present study was to investigate the effects of tympanic temperature on basic affect (i.e., pleasure-displeasure) in the course of a high-intensity exercise session. Method: One hundred seventy students performed a 10-min cycling exercise at an intensity of 80% to 85% of maximal heart rate. Heart rate, tympanic temperature, and self-reported pleasure (using the Feeling Scale [FS]) were measured twice during exercise at the end of the first minute (Min 1:00) and beginning of the last minute (Min 9:00). Results: Small increases in tympanic temperature were noted from Min 1:00 to Min 9:00 (mean change value = +0.2°C). Meanwhile, the FS scores changed in the opposite direction (mean change value = -0.2 units). However, changes in temperature only poorly predicted changes in pleasure-displeasure (R[superscript 2] = 0.05 for the linear regression, R[superscript 2] = 0.08 for the curvilinear regression). Conclusions: Slight elevated tympanic temperature occurred during the 10-min cycling exercise, but it had a negligible effect on changes in pleasure ratings. The possibility that tympanic temperature is not a valid indicator of core temperature during exercise is discussed.