Objective: To understand the anthropometric changes in paediatric patients with CHD, to evaluate their status and to assess their sport activity frequency.Methods: Of 535 children on follow up, we selected 368 Caucasian children (aged 2-18 years) with CHD, had at least one visit with measured weight and height, with no comorbidities that could influence growth. A total of 1690 complete anthropometric measurements were analyzed. Anthropometric z-scores were computed using formulae based on the LMS method according to Cacciari growth standards.Underweight, overweight and obesity were defined using BMI percentile cut-offs. Sport activity was collected through a phone interview.The CHD severity was classified as mild, moderate, severe, univentricular or unclassified.Results: Significant increase with age was observed for weight z-score [beta (95%CI): 0.03 (0.02,0.05) for one-unit of age] and BMI z-score [0.06 (0.03,0.08)] but not for height z-score. The percentage of underweight increased with disease severity, and the percentages of overweight and obese patients consequently decreased. The percentage of obesity in patients with mild CHD (5.9% [95%CI: 3.4,8.4]) was not significantly different from that in patients with moderate CHD (3.3% [1.5,5.0]), whereas it was lower in patients with severe CHD (0.4% [0.0,0.9]). No obese patients with univentricular heart defect was observed. Days spent in sport activities was equal to 1.9 [95%CI: 1.6,2.2] days/week, 1.9 [1.5,2.2], 1.4 [1.1,1.7] and 0.7 [0.1,1.3] in patients with mild, moderate, severe and univentricular CHD, respectively.Conclusions: Children with mild and moderate CHD present a risk of becoming overweight or obese that could not be underestimated and on the other hand could be prevented or reduced promoting an healthy lifestyle.