The present study was carried out to investigate the effect of barley and barley bran contaminated with Fusarium spp on growth performance and feed efficiency of fattening and growing pigs. In experiment 1, total 48 fattening Landrace pigs were used in a fattening trial for 71 days. Pigs weighing around 75 kg were allocated into different substitution groups containing 0, 10, 20 and 30% of barley contaminated Fusarium spp. In experiment 2, total 16 growing Landrace pigs were used in a growing trial for 45 days. Pigs weighing around 29.4 kg were allocated into different substitution groups containing 0, 5, 10 and 20% of barley bran contaminated Fusarium spp. Mycotoxin concentrations of barley and barley bran contaminated with 30% Fusarium spp were 0.452 and 1.049 ppm for deoxynivalenol, 8.125 and 17.646 ppm for nivalenol and 0.023 and 0.029 ppm for zearalenone, respectively. In experiment 1, no differences were found in weight gain and feed intake between control group (0%) and 10 or 20% substitution groups, but in 30% substitution group, weight gain and feed intake were significantly lower (p less than 0.05) than those in control group. After slaughtering, the extended haemorrhage of the fundus region in stomach was observed in 20 or 30% substitution groups. In experiment 2, weight gain and feed intake were not significantly different among treatment groups. After slaughtering of experimental pigs, the extended haemorrhage of the fundus region in stomach was observed in pigs fed diet with 20% substitution group. These results suggest that the feeding of diet with contaminated highly levels of Fusarium spp was negative effect on growth and feed efficiency in growing and fattening pig.