This study analyzes the translation method of epistemic modality in the translation of detective stories, focusing on four Korean translations of Edgar Allan Poe’s short story, ‘The Murders in the Rue Morgue.’ In order to examine the translation method of epistemic modality, first, the concept of modality and the system of modality were explored, second, English modal operators and Korean modal operators were categorized, and then translations ons of modal expressions were compared and analyzed. This story has been described as the first work to see Poe's writing style and form shift from Gothic novels to modern detective stories, or ratiocinative stories in a Poe’s preferred nomenclature. These detective stories are distinguished from other works in that they solve mysteries by reasoning. The ground of reasoning is propositions, and the factuality of propositions can be manifested by modality that generally refers to a speaker’s opinion about the truth of a proposition expressed by a sentence. Particularly, epistemic modality which expresses the judgment of the degree of truth of the proposition, such as speculation, conviction, and possibility, can influence the reasoning process, suggesting the wrong or right directions towards solving the mysteries in detective stories. Epistemic modality is an effective way to bring suspense and curiosity in detective stories by hiding and revealing clues. Consequently, realization of epistemic modality has a critical role in detective stories, in turn;the translation of epistemic modality is one of the important factors in translated detective stories, to influence the reasoning process and bring suspense and curiosity to the readers. Epistemic modality may be a general concept but its realization is language specific. It is realized by using various epistemic modal operators including auxiliary verbs, adjectives, adverbs, nouns, combined expressions, and orders of lexical components. The degree of commitment to the truth of a proposition, represented by modal expressions, may not be exactly the same in the source language and the target language. Given that the translation of epistemic modality is one of the important factors that influence the reasoning process and bring suspense and curiosity to stories, recognition of epistemic modality systems and their different realization in the source and target languages is essential, particularly for translating detective stories.