A 62-year-old male who had gallbladder stone was admitted because of an abnormality in abdominal CT. Abdominal CT revealed the mass lesion with smooth margin under the diaphragmatic area, whose density was higher than that of water. Both MRI T1-weighted and T2-weighted images showed a relatively high intensity. On ultrasonography, the lesion was consisted of a thin wall. On the basis of these imaging modalities, the diagnosis was considered to be cyst. The mass was resected via posterior extraperitoneal approach, and its histologic diagnosis was bronchogenic cyst containing turbid fluid. Subdiaphragmatic bronchogenic cyst is rarely reported. The characteristic findings of MRI and ultrasonography was useful for the diagnosis of a cyst with turbid contents.