In Persian, the only syllable type with consonant clusters is cvcc, where its coda can be filled with two consonants. The present article attempts to find whether these two consonant conform the sonority sequencing principle or not. For this reason, the Persian words with cvcc syllable type are gathered from Persian dictionaries and are classified based on the vowel filling the nucleus of the syllables and the consonants in the first or second slot of the coda and the following results were obtained: a. Sonority sequencing principle is confirmed in clusters nuclei are /i,u,a/. b. Sonority sequencing principle is rejected in clusters with vowels /æ, e,o/. c. Based on sonority sequencing principle, vowels in Persian make up two natural classes namely / æ, e,o/ and /i,u,a/.
