With recent advances in technology, fetal sacrococcygeal teratoma is being diagnosed increasingly during the early prenatal period by ultrasound examination. In addition, early detection of tumor related complications such as polyhydramnios, congestive heart failure, hydrops, hemorrhage, urinary tract or bowel obstruction can be followed closely in utero. Active prenatal management can improve fetal perinatal outcome by allowing planned delivery for neonatal surgery [Chisholm, C.A. et al.: Am J Perinatol 1999;16:47–50] or in some cases, fetal intervention. Additionally, families can be counseled appropriately regarding the range of outcomes. We report a case of fetal sacrococcygeal teratoma Type I diagnosed at 20 weeks with a prominent vessel supplying the tumor mass. At 23 weeks, there was a sudden appearance of an additional lobular mass, consistent with intrauterine spontaneous ruptured of a sacrococcygeal teratoma mass.