This study was conducted to investigate the effects of the vitamin D sources(skin synthesis through ultraviolet rays, vitamin D food intake, intake of vitamin D supplements ingestion) on the serum 25-(OH) D3 levels, and the growth of a child and allergy. Subjects were 296 children''s patient aged from 1 to 5 years old who visited S hospital located in Changwon City. Survey data collection was carried out by direct interview method, and biochemical data were collected using hospital records. The data was analyzed using SPSS 18.0. The results were as follows. The average concentration of serum 25-(OH) D3 was 20.41±6.55 ng/mL, which was relatively insufficient. Out of all patients, 48.3% were deficient, 44.3% were relatively insufficient, and 7.4% were sufficient. The average sunlight exposure duration per day was 58.86±49.18 minutes, and 45.9% of the subjects were using block ultraviolet rays. The preferred methods of blocking ultraviolet rays were wearing hats(35.6%), sun block(35.1%), and mask(29.3%). The most frequently consumed vitamin D food group was milk or dairy products(4.75/9 points), and major vitamin D source was milk(6.72/9 points), eggs(5.50 points), and cheese(4.30 points). The subjects of 34.1% were ingesting vitamin D supplements, and dose of vitamin D supplements was 11.96 ㎍/day on average. The average sunlight exposure hours per day, vitamin D food intake frequency, and vitamin D supplements intake were significantly correlated with serum 25-(OH) D3 levels(p<0.01∼ p<0.001). Of vitamin D sources, vitamin D supplements intake showed (+) 28.8% explanation power on serum 25-(OH) D3 concentration(F=40.550, p<0.001), and vitamin D food intake (+) and sunlight exposure hours show (+) 6.8% explanation power(F=11.714, P<0.001). The relevance between serum 25-(OH) D3 concentration and height and weight were shown as negative(-), and their explanation powers were low, showing 7.3%(p<0.001) and 5.9%(p<0.001) respectively. The results seem to be affected by age factor. Seventy-three-point-six percent of all the subjects were suffering from allergies, the most frequency was asthma(88.8%). It was showed a negative relationship between the serum 25-(OH) D3 concentration and allergies. Only 18.3% of the allergic patients were carried out with restricted diet for treatment, and restricted foods were fish·meat(33.9%), milk(19.4%), and fat group(17.7%). In recent years our society has been concerned about the lack of vitamin D in children. In that sense, this study results can be useful when discussing the intake standard of vitamin D and the effective intake method for children. In addition, it will be helpful to build the children''s nutrition policy and to plan the nutrition education program to improve the vitamin D status in children.