We aimed to analyze somatic growth of patients after total cavopulmonary connection (TCPC) as well as to identify factors influencing postoperative catch-up growth. A total of 309 patients undergoing TCPC at 4 years old or less between 1994 and 2021 were included. Weight-for-age z-score (WAZ) and height-for-age-z-score (HAZ) at TCPC and at postoperative time between 1 to 3 years were calculated. Factors influencing somatic growth were analyzed. Most frequent diagnosis and initial palliation were hypoplastic left heart syndrome (HLHS) (34%) and the Norwood procedure (51%), respectively. Median age and weight at TCPC was 2.0 (IQR: 1.7-2.5) years and 11.3 (10.5-12.7) kg, respectively. Median 519 days after TCPC, significant increase in WAZ (-0.4 to -0.2, p<0.001) was observed, but not in HAZ (-0.6 to -0.6, p=0.38). Older age at TCPC (p<0.001, OR: 2.6) and HLHS (p=0.007, OR: 2.2) were risks for low WAZ after TCPC. Older age at TCPC (p=0.009. OR: 1.9) and previous Norwood procedure (p=0.021, OR: 2.0) were risks for low HAZ after TCPC. Previous bidirectional cavopulmonary shunt (BCPS) was a protective factor for both WAZ (p=0.012, OR: 0.06) and HAZ (p=0.028, OR: 0.30) at TCPC. In patients undergoing TCPC at the age of 4 years or less, a significant catch-up growth was observed in weight-for-age z-score after TCPC, but not in height-for-age-z-score. Previous BCPS resulted to be a protective factor for a better somatic development at TCPC. HLHS undergoing Norwood were considered as risks for somatic development after TCPC.