The article delves into how epenthetic vowels in English loanwords can be analyzed from a constraint-based perspective. It is well known that some words in a language are usually affected by a wide variety of factors when they are borrowed into another language. Vowel epenthesis takes place in Korean (e.g., strike → [sɨtʰɨɾaikɨ], boss → [bos’ɨ], and march → [macʰi]) in order to avoid consonant clusters and meet the Korean syllable structure. In the case of word-final non-palatal consonants, the most unmarked vowel [ɨ] is inserted on the basis of factors like Korean phonetic/phonological patterns/ constraints. In the case of word-final palatal consonants, the high palatal vowel is inserted according to perceptional factors. Vowel epenthesis in English loanwords could be analyzed based on some constraints and their ranking (*Released-Coda, *Voiced-Coda, Max-IO, Ident-IO(release), AGRV[pal] >> Ident-IO(ObsVce), Dep-IO) within a constraint-based theoretic framework.