A series of experiments was carried out to determine the effects of supplementing acorn as a chicken feed ingredient on the chick growth, feed efficiency, nitrogen retention and metabolizable energy value. The results obtained were summarized as follows: 1. At a level of 1% supplementation to growing chick ration, tannins depressed the growth of chicks and their feed consumption, but the inclusion of methionine and choline partially alleviated the toxic effects. 2. Diet containing 2% tannin was toxic and caused depressed body weight, decrease in egg production, egg weight, Haugh units and feed consumption, but reduction in body weight and egg production were prevented to some extent by the addition of methionine and choline to the diet. 3. In the nutritionally balanced starter diets, the addition of raw acorn up to the level of 10% may replace equivalent amount of corn without adverse effect. 4. Raw acorn reduced the grow th rate of starter chicks remarkably and those treatments of water, heat and alkali improved the growth rate to some degree. Nitrogen retention were decreased when the birds fed acorn containing diets. The water soaked acorn gave the highest ME value among all the processing methods. 5. Tannin content of acorn was decreased markedly by water soaking.