Objective: To determine the outcome of antenatally suspected congenital cystic adenomatoid malformation of the lung (CCAM) over a 10 year period. Methods: Thi s is a retrospective study of all babies diagnosed antenatally in the Prenatal D iagnosis Unit and delivered in Oxford between 1991 and 2001. Data were obtained from the Oxford Congenital Anomaly Register, theatre records, and histopathology reports. Results: Twenty eight cases of CCAM were diagnosed antenatally. Five p regnancies were terminated. Data are available on all 23 of the pregnancies that continued and resulted in two neonatal deaths and 21 surviving babies. Eleven o f the 23 cases (48%) showed some regression of the lesion antenatally, and four of these cases appeared to resolve completely on prenatal ultrasound. Three of the 23 babies (13%) were symptomatic in the early neonatal period, and three de veloped symptoms shortly afterwards. Seventeen of the 23 babies (74%) were asym ptomatic, of whom 12 had abnormalities on chest radiograph or computed tomograph y scan and had elective surgery. Two babies (8%) had completely normal postnata l imaging, and three had abnormalities which resolved in the first year of life. Seventeen of the 23 babies (74%) had surgery. Histology at surgery was heterog eneous. Of the 23 live births, all 21 survivors (91%) are well at follow up or have been discharged. Conclusions: All babies diagnosed antenatally with CCAM re quire postnatal imaging with computed tomography irrespective of signs of antena tal resolution. In asymptomatic infants, the recommendations are close follow up and elective surgery for persistent lesions within the first year of life. Hist ology at surgery was heterogeneous, and this should be considered when counselli ng parents. Methods: Thi s is a retrospective study of all babies diagnosed antenatally in the Prenatal D iagnosis Unit and delivered in Oxford between 1991 Results: Twenty eight cases of CCAM were diagnosed with antenatally. Five p regnancies were terminated. Data are available on all 23 of the pregnancies that continued and resulted in. Data were available on all 23 of the pregnancies that continued and resulted. in two neonatal deaths and 21 surviving babies. Eleven of the 23 cases (48%) showed some regression of the lesion antenatally, and four of these cases Established to resolve completely on prenatal ultrasound. Three of the 23 babies (13%) were symptomatic in the early neonatal period, and three de veloped symptoms shortly afterwards. Seventeen of the 23 babies (74%) were asym ptomatic, of whom 12 had abnormalities on chest radiograph or computed tomograph y scan and had elective surgery. Two babies (8%) had completely normal postnata l imaging, and three had abnormalities which resolved in the first year of life. Seventeen of the 23 babies (74%) had surgery Of the 23 live births, all 21 survivors (91%) are well at follow up or have been discharged. Conclusions: All babies diagnosed antenatally with CCAM re quire postnatal imaging with computed tomography irrespective of signs of antenas tal resolution. In asymptomatic infants, the recommendations are close follow up and elective surgery for persistent lesions within the first year of life. Hist at at surgery was heterogeneous, and this should be considered when counselli ng parents.