We investigated the effects of biotin deficiency on the sense of taste in rats. Male wistar rats aged 3 weeks, were divided into three groups: Control group (C), pair-fed group (PF) and biotin-deficient (BD) group. All rats in the three groups were fed for Sweeks. 48-h two-bottle preference test was conducted on the 3-4th and 7-8th week of each feeding. Food intake and body weight were decreased from the 3rd week in the BD group. Plasma and liver biotin levels were significantly decreased in the BD group. The 48-h preference test showed that the preference ratios for salty taste at 300 and 500 mM NaCl on the 3rd week were relatively higher in the BD group than in the C and PF groups. However, there were no significant differences in the preference ratios for salty taste on the 7th week among the three groups. For the bitter taste test on the 4th week, the preference ratios at all concentrations of caffeine used were relatively higher in the BD group than in the C and PF groups. On the 8th week, the preference ratio for bitter taste at 3 mM caffeine was higher in the BD group than in the PF group. These results indicate that biotin deficiency has an effect on the sense of taste in rats. The results also suggest the possibility that the recognition threshold value for taste is increased in BD rats.