A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether prophylactic administration of steroids is of benefit to children undergoing cardiac surgery? Altogether 302 papers were found using the reported search, of which six represented the best evidence. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses were tabulated. We conclude that steroids may reduce Troponin I release, CRP and reduce Interleukin-6. In addition, two studies, each in only 30 patients, found some evidence for improvements in clinical parameters such as ICU stay and fluid requirement. These findings need confirmation prior to any firm recommendations as to the clinical benefits of steroids.