A device was developed that allowed for the objective assessment of human female eroticism by continuously measuring temperature changes of the labia minora. During exposure to an erotic motion-picture, nine of ten adult female volunteers experienced increases of their labial temperature (ranging from about 0.10°C to 1.38°C), as measured by a sensitive thermistor-clip, that were significantly higher than during a non-erotic film. The labial temperature of the remaining subject decreased by a small amount during the film. No consistent changes were exhibited in a reference temperature measured from a position on the upper chest during either stimulus condition. Subjective levels of eroticism, obtained by self-report, were significantly correlated with labial temperature changes elicited by the stimuli.