Intrauterine surgery of the fetus or fetal adnexae is spreading rapidly throughout the world. In a broad sense, intrauterine surgery includes any procedure in which a medical device is purposely placed within the uterine cavity. For most physicians, however, the concept of intrauterine surgery excludes such commonly performed procedures as amniocentesis and chorionic villous sampling. Rather, the term usually refers to techniques requiring specialized knowledge, experience, and most especially, instrumentation. Procedures most commonly mentioned in discourses on intrauterine surgery include those specifically developed for the treatment of such serious anatomic defects as congenital cystic adenomatoid malformation (CCAM), sacrococcygeal teratoma (SCT), lower urinary tract obstruction (LUTO), myelomeningocele, aortic or pulmonic stenosis, gastroschisis, iatrogenic amniorhexis, twin‐to‐twin transfusion syndrome (TTTS), and twins discordant for severe anomalies. As no one person in the world is an expert in every one of these procedures, the remainder of this chapter is divided into individual sections, each authored by someone widely recognized as a leader in the treatment of that particular anomaly.