The enhancing effect of vitamin A on the occurrence of amyloid arthropathy in Brown layer chickens is reported. In this study, 36 female and 36 male chickens were used. The chickens were allocated into 3 groups. Group I (Vitamin A group) was fed a diet which contained high levels of Vitamin A (75,000 I.U/kg), whereas group II (positive control) and group III (negative control) were fed a diet containing normal levels of vitamin A. In the fifth week of the experiment Enterococcus faecalis (10(9) cfu/ml) was injected into the left femoro-tibial joint in groups I and II (in order to produce amyloid arthropathy) and 0.9% NaCl (0.25 ml) in group Ill. At the end of the study, the amyloidosis occurrence rates and the severity of amyloid accumulation were compared. The occurrence of amyloid arthropathy in the vitamin A, the positive control and the negative control groups was 19/20 (95%), 18/24 (75%) and 0/24 (0%), respectively, and the differences among the groups were statistically significant (P < 0,01). Severe amyloid accumulation was observed in 8/20 (42.1 %) chickens in the vitamin A group, while no severe accumulation was found in the positive control group (P < 0,05). In conclusion, these data showed that high levels of vitamin A in the diet can enhance the occurrence and the severity of amyloid arthropathy induced with E. faecalis in Brown layer chickens.