Echocardiography provides adequate preoperative imaging for most young infants with congenital heart disease (CHD). When anatomic details require further clarification, cardiac magnetic resonance imaging (CMRI) may be useful but adds the risks of sedation or general anesthesia for a vulnerable population. This study aimed to determine the safety of CMRI and its yield of additional significant information for this population. The study identified all infants age 90 days or younger with preoperative echocardiography and a CMRI from the period 2002-2012. Indications, complications, and imaging results were collected. The additional CMRI information was defined as "significant" if it altered surgical management or "not significant" if it did not. Associations between indications for CMRI and the likelihood of new significant findings were sought. For 137 infants (58% male), CMRI was performed at a median age of 5 days (range, 0-89 days). The CMRI yielded additional information for 76% (104/137) of the patients. The additional findings were significant for 69% (72/104) of these patients. The incidence of significant new findings was similar among indication categories. All the infants were intubated. Complications occurred for 5% of the patients, including one subject with a bradycardic event that prevented completion of the exam and six patients with transient vital sign changes that allowed exam completion. More than 50% of young infants with CHD who underwent preoperative CMRI had new findings affecting surgical management. Among these patients, CMRI-associated complications were few and predominantly minor for intubated infants. Further studies to determine standard preoperative criteria for the use of CMRI for infants with CHD may help to define appropriate cost-effective use of this diagnostic method.