Abstract: Infectious bursal disease (IBD) is an important viral disease of chickens due to significant economic loses in the industry resulting from high mortality and immunosuppression. An experiment was conducted to determine the efficacy of an attenuated live "intermediate" strain IBD vaccine of Malaysian isolate given to broiler chickens via feed. One hundred and twenty day old broiler chicks were divided into 3 groups namely: group A (feed based IBD vaccination), group B (IBD vaccination via intraocular route) and group C (control). The chickens in groups A and B were vaccinated at day 14 with an attenuated live "intermediate" strain IBD vaccine of Malaysian isolate (104.5EID50/0.1ml) via feed (about 0.1ml/chick) and intraocular route (0.1ml/chick), respectively. Feed and water were given ad libitum, and the chickens were monitored for any clinical abnormalities throughout the trial. Eight chicks in the control group were sacrificed at 1, 7, 14, 21, 28, 35 and 42 days of age. Eight chickens each from the groups A and B were sacrificed at 21, 28, 35 and 42 days of age. Body weights were taken and serum samples were collected for IBD antibody detection using enzyme linked immunosorbent assays (ELISA) prior to necropsy. On necropsy, the gross lesions were recorded and the bursa of Fabricius was weighed and fixed in 10 % buffered formalin for histopathology examination. The study showed that no clinical sign of IBD observed in all groups throughout the trial. The body weights in all groups were not significantly different (p<0.05). Gross lesions were confined to the bursa of Fabricius at day 21 of age in the group A, and at days 21 and 28 of age in the group B. The bursa weight and bursa to body weight ratio in groups A and B were generally lower than control group throughout the post vaccination period. The lesions scores in group A remained mild to moderate throughout post vaccination period and showed sign recovery at day 42. The lesions score in the group B was moderate at day 21 of age and reduced to mild to moderate thereafter. Both routes of vaccination were able to induce protective immunity against IBD infection at days 35 and 42 of age. It was concluded that the feed based IBD vaccination at 14-day-old broiler chickens using attenuated live "intermediate" strain IBD vaccine of Malaysian isolate is safe and successfully induce protective level of IBD antibody.