Previous investigations have shown that magnetic resonance imaging (MRI) can be employed as an efficient non-invasive diagnostic tool in studies on Egyptian mummies. MRI, moreover, because it produces especially clear images of well-hydrated tissue, could be a particularly effective diagnostic option for mummies that still retain humidity within tissues or organs. Therefore, in the present study, we tested MRI on a 17th century mummy, one of the most perfectly preserved 'hydrated mummies' ever found in Korea, in order to determine the quality of images that could be obtained. We found that the diagnostic value of an MRI scan of the hydrated mummy was not inferior to that of a computed tomography scan. The T1- and T2-weighted magnetic resonance (MR) signals showed unique patterns not easily obtained by computed tomography, the resultant MR images revealing the organ specificities clearly. Overall, the quality of the MR images from the hydrated mummy was superb and the scientific value of MRI in the study of hydrated mummies should not be underestimated.