The present study compares two approaches to syllabification in Harmonic Serialism (HS): one as a distinct phonological operation and the other as a non-distinct operation. According to McCarthy (2007), GEN in Harmonic Serialism is confined to a single unfaithful operation at a time. If syllabification is a non-distinct and automatic operation, it can apply in a single pass to a series of segments (McCarthy 2009). However, if syllabification is treated as a distinct and separate operation (Elfner 2009), it has to take place sequentially, each syllable generated in a separate step just like other unfaithful operations such as deletion, insertion, or feature change. By adopting the framework of HS, this study considers an interaction between tensing, a feature changing operation, and consonant cluster simplification. The findings of this study are that syllabification in HS should be a distinct operation, confirming the argument of Elfner (2009), and that HS gives a better account of opacity in tensing than OT-CC does in terms of descriptive and explanatory adequacy.