The tridimensional theory of personality posits that traits belonging to a personality spectrum called 'reward dependence' are determined in part by the neurotransmitter norepinephrine (NE). We hypothesized that urinary levels of the NE metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) would be significantly correlated to the reward dependence score on the Tridimensional Personality Questionnaire (TPQ). Twenty-seven never psychiatrically ill subjects collected urine for MHPG measurements and completed the TPQ. There was a significant correlation between the reward dependence score and the level of MHPG. MHPG levels was not associated with the other two personality dimensions, novelty seeking and harm avoidance. This preliminary study supports the hypothesis that reward-dependence traits are in part determined by NE.