An 18-year-old woman at 18 weeks' gestation presented with abdominal pain and jaundice. After extensive evaluation, she was diagnosed as having a choledochal cyst. Ten days after percutaneous drainage, she underwent complete excision and Roux-en-Y hepaticojejunostomy anastomosis. At term, she delivered vaginally without complications. Although choledochal cysts are rare in pregnancy, it is important for the obstetrician to be familiar with the presentation and the best treatment modalities available. Delay in diagnosis and inappropriate treatment can result in maternal morbidity and fetal mortality.