As an attempt to improve the nutritional status of Korean rural pre-school children, anthropometry, clinical examination, and hematological parameters(Hb, Ht, and serum albumin) are measured. Six kinds of diet supplemented with 0, 2.5, 5.0, 7.5, 10.0 and 20.0 mg Fe(as ferrous sulfate) were used for 10 weeks. Subjects were 349 pre- school children aged from 1 to 5 years old living in An-gam-my-on and Bong-dang-myon, Hwa-seung-goo, Kyong-gi-duo, and the supplementary diet was a product of the Model Nutritional Enterprise Factory in Wuen-sueng-goon, Gang-won- duo. The results obtained were as follows : 1) Physical development of subject children were within normal range during the feeding trial period of 9 weeks. 2) From the results of clinical examination, no children showed nutritional deficiency signs. 3) Iron free supplementary diet group( control group ) among other subject children also showed some improvement of hemoglobin level ana frequency of anemia. 4) The amount of iron fortified as supplemental diet was effective in 5.0-7.5 mg Fe per child per day, no further effect was observed by adding of more iron. 5) The values of hematocrit and serum albumin also improved by providing the supplementary diet.