Fetal congenital cystic adenomatoid malformation (CCAM) can progress to nonimmune hydrops, and the mortality rate of CCAM with hydrops is reported to be nearly 100%. We describe three microcystic CCAM cases in which the fetal condition improved after maternal betamethasone therapy. The median gestational age at steroid administration was 23 5/7 weeks' gestation. The CCAM decreased in size in all cases. Our series showed a 100% hydrops resolution rate (2/2) and a 100% survival rate (3/3). Our experience suggests the efficacy of betamethasone treatment on fetuses with microcystic CCAM who have fluid collection or are at risk of developing hydrops.