The present studies were undertaken to examine the hypothesis that sucrose feeding at weaning may alter the preference for sucrose in the adolescence. Chronological changes of hypothalamic dopamine (DA), its metabolite, 3,4-dihydroxy-phenylacetic acid (DOPAC) and norepinephrine (NE) contents were also measured by HPLC. In 21 day-aged rats, 10% sucrose or water was given as drinking water for 3 weeks. From 9 weeks, all animals were maintained under a free choice between 30% sucrose solution and water. Sucrose-ingested rats more preferred to 30% sucrose solution than control rats and body weight gain of sucrose group was significantly greater than that of controls. Hypothalamic DA content was significantly decreased at 6 and 13 weeks and the DOPAC/DA ratio increased at 3, 6, and 13 weeks later. In contrast, hypothalamic NE concentration was not changed at all. The data obtained herein suggest that sucrose feeding at weaning alters the preference for sucrose, resulting in an overweight gain, and that the observed increase of hypothalamic DA metabolism may be involved in the altered preference for sucrose.