This study was carried out to investigate the effects of breakfast service on nutritional status, hematological status, and attentiveness of children in low-income families. The subjects were 19 boys and 13 girls between 7 and 11 years old. The subjects were divided into a control group and a breakfast service (BS) group, in which 12 boys and 5 girls received breakfast from February 1 to December 31, 2010. The results can be summarized as follows: intakes of energy, protein, carbohydrate, calcium, iron, zinc, vitamin A, vitamin $B_2$, niacin, and vitamin C in the BS group were significantly higher than those in the control group. In the BS group, the intakes of calcium, folic acid, and vitamin C were lower than 75% of recommended intake levels. There were no significant differences in the total blood protein level and total cholesterol level between the BS group and control group. A blood albumin level was significantly higher in the BS group than in the control group. Systolic blood pressure was higher in the BS group than in the control group, whereas the diastolic blood pressure showed no significant difference between the groups. A dietary attitude score increased according to breakfast service and nutritional education. No significant differences were found in the capacity value and continuity value between the two groups, but the control value was significantly higher in the BS group than in the control group. Therefore, to sustain the effect of breakfast service and improve nutritional status for children skipping breakfast in low-income families, nutrition intervention services, as well as legal and financial support by the government should be provided.