The purposes of this study was to describe the clinical correlation of mass size and gestational age, prognostic factors in sacrococcygeal teratoma (SCT) at a tertiary pediatric surgery, University of Ulsan College of Medicine and Asan Medical Center (AMC), Seoul, Korea. Fifty five patients admitted to the AMC with a SCT between May 1989 and April 2013 were included in this retrospective review. Mean follow up was 861 days. Mean maternal age at delivery was 30 ± 2.7 year, mean gestational age (GA) was 36.9 ± 3.6wks, and preterm delivery was 21.8%. Birth body weight was 3182 ± 644 g and male vs. female ratio was 1:2.05. We can't find significant difference between Caesarean section and maternal age at delivery (p = 0.817). But, caesarean section was favored by gestational age (p = 0.002), larger tumor size (p = 0.029) or higher tumor weight fraction rate to birth body weight (p = 0.024). Type I was 13, II 21, III 17, and IV 3 according to Altman et al. classification. The tumor component was predominantly cystic(>50%) in 73.1%. And the majority histological classification of tumors were mature teratoma (70.3%). The motality rate was 5.5%. Three patients expired because of postpartum bleeding, post-op bleeding related complication such as DIC. SCT recurred in four patients. The interval between first and second operation was 206.2 ± 111.0 d (range 53~325 d). In two patients, serum AFP levels were elevated at a regular checkup without any symptom, and subsequent imaging studies revealed SCT. The most common cause of death was bleeding and bleeding related complication. So Caesarean section and active peripartum and perioperative management will be needed for huge solid SCT. In the case of Yolk sac tumor or huge immature teratoma, possibility of recurrence have to be always considered, so follow up by serial AFP and MRI is important for SCT management.