Mucinous cystic neoplasms of the pancreas are rare tumors that represent 10% of cystic pancreatic tumors. They are potentially sex hormone-sensitive. However, mucinous cystic neoplasms occurring during pregnancy are relatively uncommon. A 33-year-old woman in her ninth week of gestation was referred to us due to abdominal pain for two months. Magnetic resonance imaging revealed a well-defined unilocular cystic lesion at the tail of the pancreas, measuring 7x6.4 cm. The patient underwent tumor resection with distal pancreatectomy and splenectomy during the second trimester to prevent the potential risk of rupture of the neoplasm, rapid growth, and/or intrauterine growth restriction. Histopathological examination revealed a mucinous cystadenoma with no atypia or malignancy. The patient completely recovered from the surgery and had a healthy full-term baby. This case shows the benefit of performing the surgery during the second trimester compared to the potential risk of delaying the surgery.