We evaluated familial aggregation of metabolic syndrome components in obese children. A total of 198 obese children and their parents were enrolled in a prospective cohort study and were evaluated for the intrafamilial relationships of metabolic syndrome components. Metabolic syndrome was diagnosed in 25 (26%) of 96 obese boys, in 27 (26.4%) of 102 obese girls, in 53 (34.8%) of 152 mothers, and in 37 (33.6%) of 110 fathers. Compared with obese boys, obese girls showed higher correlations with their mothers for waist circumference, systolic blood pressure, and high-density lipoprotein cholesterol and with their fathers for total cholesterol. Compared with obese girls, obese boys showed higher correlations with their fathers for waist circumference, body mass index, high-density lipoprotein cholesterol, triglyceride, fasting plasma glucose, and diastolic blood pressure and with their mothers for total cholesterol, low-density lipoprotein, and triglyceride. There was a significant resemblance of metabolic syndrome and its components among families. Gender-related correlations should be considered for future interventions.