Leucaena leucocephala has been utilized with limit as livestock feeds due to the existence of a toxic mimosine. So, it is necessary to induce mimosine toxicity to the experimental animals to study its cure and elucidation. The studies on inducing mimosine toxicity by feeding L. leucocephala seed powder to chicks were carried out. Chicks were fed normal diets with 0, 10, 15 and 20% of L. leucocephala seed powder, and 1% crude mimosine for 12 days. Chicks fed toxic diets had decreased food intake and body weight gain, leg weakling symptom and enlargement of kidney. Mimosine was detected in the tissues of chicks fed the poisonous diets. Chicks orally administered crude mimosine were found to have alleviated the decrease of food intake and body weight gain. Chicks fed 15% seed powder diet for 12 days at 1-5 weeks of age, respectively, had decreased food intake and body weight gain regardless of growing stages, but mimosine content in the tissues decreased with growing age. After feeding 15% seed powder diet for 12 days, chicks were fed a normal diet for 20 days. Food intake of the chicks increased from the first day when the diet was changed to normal diet. Mimosine considerably existed in the feather and thyroid gland on the 20th day, but disappeared in the kidney, serum, liver and excretion. So, male broiler chicks were found to be rapidly and easily induced to mimosine toxicity by feeding 15% L.