Ovarian cysts are found in 32% of necropsies performed to neonates. They can also be diagnosed during gestation by ultrasonography. The clinical evolution of these cysts is variable, but in most cases the prognosis is favorable. Some complications such as ovarian torsion, bleeding, rupture and peritonitis have been described. We report two newborn girls with ovarian cysts, diagnosed during gestation. One required an emergency operation due to vomiting and abdominal distension, interpreted as a possible torsion of the cyst. The second girl was operated at the fourth day of life, finding a left ovarian cyst with torsion of the pedicle. Both girls had a favorable postoperative evolution (Rev Méd Chile 2003; 131: 665-668)