A total of 468 day-old broiler chicks of Shaver strain was used in this experiment to study the effects of substitution of different levels of sodium sulfate for methionine on the growing performance, nutrient utilizability, serum amino acid content and retention of nitrogen and sulfur for a period of 6 weeks. Three levels of methionine (0, 0.2 and 0.4%) and four levels of sodium sulfate (0, 0.1, 0.3 and 0.6%) were arranged by 3×4 factorial design. The results obtained from a series of experimentation are summarized as follows; 1. A little improvement in growth rate and feed efficiency of chicks was obtained from adding sodium sulfate to a diet deficient in sulfur amino acids, although no statistical significance was found. 2. Concentration of almost all the neutral and acidic amino acids in serum hydrolyzates was decreased by feeding sulfur amino: acid-deficient and inorganic sulfate-supplemented diets. This finding was interpreted to mean that more amino acids had been incorporated into muscle protein than into serum protein by methionine-sparing action or some other possible specific actions of sulfate. The concentration of methionine itself was not decreased. This would mean that free methionine concentration in: serum was increased. 3. Dry matter and nitrogen free extract utilizations by chicks were increased with increasing levels of sodium sulfate but were decreased by increasing the dietary methionine level. Metabolizable energy content per kilogram of diet was also increased by adding sodium sulfate to the diet with low level of methionine and decreased by methionine supplementation (P$lt;0.01). 4. Nitrogen retention data showed the similar trend to those of utilizability of the other nutrients (P$lt;0.01). Significant interaction between methionine and sulfate was also found (P$lt;0.05). 5. Data for sulfur balance were largely dependent on nitrogen balance data with correlation coefficient, r=0.81 (P$lt;0.01). It is concluded from the results that growth response of chicks to sodium sulfate was at lean partially attributed to the action of sulfate to enhance utilizability of some nutrients and that sulfur metabolism was intimately related to metabolism of nitrogen. In this regard, more extensive studies are to be made to set up the metabolic significance of sulfur and dietary requirement of animals for sulfur.