The purpose of this study was to examine the dietary habits and nutrient intakes of school-aged children participating in extracurricular classes, to with regards to class schedule. Three-hundred and two students from Seoul were selected and classified into two groups. One group attended extracurricular classes less than 12.43 hours per week, which was determined as the average number of hours per week(AELT, n=147). The other group attended extracurricular classes more than 12.43 hours per week(AEMT, n=155). The average student age in both the AELT and AEMT groups was 11.9 years, respectively. In terms of height and weight, there were no significant differences between the two groups. AELT received significantly more hours of sleep than AEMT(p<0.01), and there were significantly more responses with regard to lack of sleep in the AEMT group than in the AELT group(p<0.05). In a survey on 17 clinical symptoms regarding health, the AEMT group had significantly higher response rates than the AELT group in the following sections: no appetite (p<0.001), dizziness(p<0.001), headache(p<0.01), tiredness(p<0.01), cold symptoms(p<0.05), and sore eyes(p<0.05). Meal time irregularity was significantly higher than AEMT than in AELT(p<0.05). Approximately 50% of the subjects were picky eaters, and 40% and 20% skipped breakfast or dinner, respectively. The average energy intakes for AELT and AEMT were 2122.2 kcal and 2061.5 kcal, respectively, and there was no significant difference between the two groups. AEMT consumed significantly lower quantities of protein, animal fat, vitamin $B_6$, calcium, and phosphorus(each p<0.05) as compared to the AELT group. Beverage intake was significantly higher in AEMT than AELT(p<0.05). The number of hours in extracurricular classes showed a significant negative correlation with the intakes of protein, animal protein, animal fat, vitamin $B_6$, folate, calcium, plant calcium and phosphorus(each p<0.05). The number of hours in extracurricular classes also showed a significant negative correlation with soy foods intake(p<0.05). These results suggest that continuous and systematic nutritional education should be performed in order to prevent and improve the unbalanced diets and problematic of dietary habits that may result in students due to attendance in extracurricular classes.