||The present paper examines the process of loanword syllable adaptation in tetrasyllabic words in Persian, within an Optimality-theoretic framework. In Persian, consonant clusters are avoided in onset position. As a result, the loanwords borrowed from other languages which have complex onsets, when introduced into Persian, are adapted to fit the syllable structure of the target language. When placed word-initially, the onset cluster is generally resolved by the insertion of an epenthetic vowel. However, this vowel epenthesis occurs in a split pattern, as it does in many other languages. In this study, following Gouskova’s (2001) proposal, we argue that this split pattern in loanword syllabic adaptation can best be explained to be an effect of the Syllable Contact Law (SCL). That is, when the two segments in the onset cluster have a rising sonority sequence, the cluster is broken up by the process of anaptyxis; while in sequences of falling sonority, the cluster is resolved through the process of prothesis. It is argued that, this pattern uniformly holds true at least as far as the dictionary-derived data in the present study are concerned. For the exceptional cases of /SN/ and /SL/ clusters-not attested in our data set, but still present and frequently referred to in the literature-we propose the addition of two positional faithfulness constraints of the DEP-V/X_Y family (Fleischhacker 2001) to our set of universal constraints to account for all the possible cases of loanword syllabic adaptation in Persian.