The incidence of chylothorax is reported from 1–9% in pediatric patients undergoing congenital heart surgery. Effective evidenced-based practice is limited for the management of post-operative chylothorax in the pediatric cardiac intensive care unit. The study characterizes the population of pediatric patients with cardiac surgery and chylothorax who eventually require pleurodesis and/or thoracic duct ligation; it also establishes objective data on the impact of various medical interventions. Data were obtained from the Pediatric Health Information System database from 2004–2015. Inclusion criteria for admissions for this study were pediatric admissions, cardiac diagnosis, cardiac surgery, and chylothorax. These data were then divided into two groups: those that did and did not require surgical intervention for chylothorax. Other data points obtained included congenital heart malformation, age, gender, length of stay, billed charges, and inpatient mortality. A total of 3503 pediatric admissions with cardiac surgery and subsequent chylothorax were included. Of these, 236 (9.4%) required surgical intervention for the chylothorax. The following cardiac diagnoses, cardiac surgeries, and comorbidities were associated with increased odds of surgical intervention: d-transposition, arterial switch, mitral valvuloplasty, acute kidney injury, need for dialysis, cardiac arrest, and extracorporeal membrane oxygenation. Statistically significant medical interventions which did have an impact were specific steroids (hydrocortisone, dexamethasone, methylprednisolone) and specific diuretics (furosemide). These were significantly associated with decreased length of stay and costs. Dexamethasone, methylprednisolone, and furosemide were associated with decreased odds for surgical intervention. These analyses offer objective data regarding the effects of interventions for chylothorax in pediatric cardiac surgery admissions. Results from this study seem to indicate that most post-operative chylothoraxes should improve with furosemide, a low-fat diet, and steroids.