5,5-Dimethylhydantoin (DMH) produced by degradation of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) may remain a residue on foods that are not washed or further processed before consumption. However, there is no test method related to DMH in Korea. In this study, DMH was quantified by gas chromatography-mass spectrometer (GC-MS) detector. DMH test method was compared and applied to determine the DMH content in various foods distributed in Korea and Australia. In addition, method validation and measurement uncertainty were performed for the established analytical method. As a result, the determination coefficient value (R