Investigating and comparing English vowels $/{varepsilon}/;and;/{ae}/$, and their-supposedly- corresponding vowels in Korean /ㅔ/ and /ㅐ/, this study addresses the following questions: Do Koreans pronounce/ㅔ/ and /ㅐ/ differently? Do they pronounce English $/{varepsilon}/;and;/{ae}/$ differently? And what is the relationship between the Korean vowels and the English vowels? Is the conventional correspondence (/ㅔ:${varepsilon}/$, and /ㅐ/:${ae)/$ appropriate? The results showed that 24 Korean male college students distinguish neither Korean /ㅔ/ and /ㅐ/ nor English $/{varepsilon}/;and;/{ae}/$, thus suggesting that their inability to distinguish the two vowels in their native tongue has an effect on their production of the English vowels. While not distinguishable within a language, Korean /ㅔ/ and /ㅐ/ still form a separate group from English $/{varepsilon}/;and;/{ae}/$. But Korean-Produced $/{varepsilon}/;and;/{ae}/$ are significantly different from American-produced $/{varepsilon}/;and;/{ae}/:$ Korean-produced $/{varepsilon}/;and;/{ae}/$ have much lower F1 and F2 than American-produced counterparts. Accordingly it is advised that, in learning English pronunciation, Korean students should be instructed to take the English vowel system as a separate system from Korean one, and thus, not to substitute Korean vowels for English vowels. And students should be provided with specific instructions on the articulatory differences between English vowels and Korean vowels. For example, Cey should be instructed to lower their jaws more for English $/{varepsilon}/;and;/{ae}/$ than for Korean /ㅔ/ and /ㅐ/.