MR assessments of ovarian cystic lesions are usually based on morphological features, signal intensities and enhancement with contrast media. This study was performed to evaluate the usefulness of the steady-state free precession (SSFP) diffusion imaging of cystic ovarian lesions for analyzing cystic contents.Sixty-one ovarian cystic lesions in 37 patients were examined. The diffusion-related coefficient (DRC) and the ratio of the relative apparent diffusion coefficient of the lesion to that of subcutaneous fat tissue (rADC(L)/rADC(F)) were calculated from SSFP diffusion images.The DRCs and the rADC(L)/rADC(F) ratios in endometrial cysts and in the fatty parts of dermoid cysts were significantly lower than in other cystic tumors.SSFP diffusion imaging can be included in clinical practice to analyze ovarian cystic lesions within a short scan time; the DRC and the rADC(L)/rADC(F) ratio are useful for evaluating cystic contents.