Objective To investigate the CT and MRI manifestations of ovarian immature teratoma. Data and methods A retrospective analysis of CT and MRI data of 8 cases of surgically and pathologically confirmed immature teratoma of the ovary was performed. Three cases showed high and low mixed densities on CT scan, with multiple small cystic hypointense shadows, “fragmented” fatty shadows and scattered high-density calcification foci, and “ragged” enhancement on enhanced scan; five cases showed high and low mixed signals on MRI, with multiple long T1 and long T2 signal cystic shadows of different sizes and scattered fragmented short T1 and long T2 signal foci. In five cases, the solid part of the MRI showed high-low mixed signal, multiple long T1 and long T2 signal cystic shadows of different sizes, scattered fragmented short T1 and long T2 signal fatty tissue and irregular long T1 and long T2 signal solid soft tissue shadows, and in four cases, the solid part showed flocculent enhancement on enhancement scan. Conclusion: Immature teratoma of the ovary has characteristic CT and MRI manifestations.