During a 5-year-period, 17 cases of congenital adenomatoid malformation of the lung were observed in the Department of Pediatric Surgery of Bologna University-S. Orsola-Malpighi Hospital; 16 cases were diagnosed in utero by ultra-sound. 13 patients had prenatal diagnosis between 21 and 23 weeks of gestation; 2 cases were diagnosed at 25 weeks and another one at 26 weeks. The other case came from another hospital, and the diagnosis was accidentally detected postnatally. In 3 cases the parents decided to terminate the pregnancy 3 cases had spontaneous improvement during the last weeks of gestation, and were perfectly normal at birth. One case was lost to follow-up; all remaining patients underwent resection. Among these patients only one was a nonsurvivor, while 9 have completely recovered. However, one patient developed persistent pulmonary hypertension, which could successfully be treated with drugs, another underwent laser treatment for laryngeal stenosis due to intubation. A special epidemiological information: 13 out 17 cases (76.5%) were female.