It is controversial whether Korean allows the Nominative/Genitive alternation as found in Japanese. While Yang (2000) argues that the Case alternation does exist in Korean, Sohn (1997) argues that there is no Nominative/Genitive alternation in Korean, based on the examples with an adverb placed in front of a Genitive subject. The purpose of this research is to statistically investigate whether such Case alternation is possible in Korean. We conducted a series of ANOVAs for two Case marker (Nominative/Genitive) types. The results showed a significant effect on Case marker: the rating was far higher for Nominative Case sentences than for Genitive Case sentences. Therefore, the results suggest that there is no Nominative/Genitive alternation in Korean, in favor of Sohn’s (1997) claim.