This study was conducted to investigate the interaction of aflatoxin and vitamin D₃. The 336 broiler chicks (Hubbard) of mixed sex were allocated to triplicate 8 (2x4 factorial) treatment groups. The 0 or 0.5ppm of aflatoxin Bi (AFB) and 0, 500, 1,000 or 1,500IU/Kg of vitamin D₃(VD) were supplemented to the basal diet. After 3 weeks of feeding period the blood and organs were collected from 2 chicks of each sex per group. The Ca content in serum increased when AFB was fed (p$lt;01). The Ca of serum increased according to the increasing level of VD. However, no significant differences were found among groups fed different levels of VD. The interaction between AFB and VD was recognized (p$lt;05). The P contents of serum were similar among different treatment groups. The alkaline phosphatase activities in serum of chicks fed AFB were higher than those of non-supplemented group, those of chicks fed different levels of VD were not significantly different and any interaction between AFB and VD was not recognized. The weight of liver increased when fed AFB (p$lt;05). As the level of VD increased, the liver weight decreased, but no significance was found. The interaction of AFB and VD was not shown. The pancreas weight decreased when fed AFB (p$lt;05), those of chicks fed different levels of VD were similar, and no significant interaction was found. The spleen weights of birds fed different levels of AFB or VD were similar. The weight of non-fat dry tibia were increased by feeding AFB (p$lt;05) The total lipid content in liver increased when fed AFB (p$lt;05), but VD feeding showed no significant differences. However, the contents of phospholipid and total free fatty acid in liver were not significantly different among treatments. The mean total protein in liver of chicks fed AFB was lower than that of non-supplemented group, and that of chicks fed 1,500IU/Kg of VD was similar to that of non-supplemented group. However, the interaction of AFB and VD was shown (p$lt;01). The optical density at 510㎚ (violet color) of liver of birds fed 0 or 0.5ppm AFB were similar, but chicks fed 1,500IU/Kg of VD showed somewhat higher density than that of non-supplemented group (p$lt;05). The interaction between AFB and VD was recognized (p$lt;05).