This study evaluated changes in growth parameters after pediatric heart transplantation and identified factors associated with the changes after pediatric heart transplantation (OHT). We retrospectively evaluated the somatic growth of 46 children <11 yr of age who underwent OHT for changes in weight, height, and BMI. The patient age range was 3.5 months to 10.7 yr. Gain in Z score for weight and BMI was significant at six months post-OHT (mean weight Z score changed from −1.1 to −0.1 and mean BMI Z score changed from −0.1 to 1.3; p < 0.001). After six months post-OHT, there was no further significant change in weight or BMI Z score. Height Z score did not show significant change from pre-OHT at six months, one yr, or two yr post-OHT. Eight patients (17%) became overweight during the two-yr follow-up period as evidenced by a BMI Z score > 2. Multivariate analysis showed length of steroid treatment as a predictor for negative height Z score change, and age at transplant as a predictor for positive height Z score change. Post-OHT, weight significantly increases without proportional increases in height, resulting in a significant proportion of these children becoming obese. Length of steroid therapy is negatively related to the “catch-up” linear growth following OHT.