Abstract: Objective RNA was one of the main forms of dietary nucleotides in foods and human milk.The effects of yeast RNA on maturation of early weaned rats were studied.Methods SD rats aged 18 days were placed on a purified diet or the same diet supplemented with 1% yeast RNA and fed for 5 days.Results The two groups were not significantly different for meach other in body weight and small intestinal weight,length,mucosal weight.Morever,as the maturation markers of the intestinal epithium,the enzyme activities of sucrase,lactase,maltase and alkaline phosphatase were not improved by supplementary RNA.Conclusion Dietary RNA may not change the maturation of small intestinal epithelium in early weaned rats.