Initial sC clusters have been widely debated and thoroughly analysed in the pho-nological literature. This paper deals specifically with the syllabic status of sC clusters in Sar-dinian. In current Sardinian, a sharp partition is observed: Logudorese does not tolerate word-initial sC clusters and a prosthetic vowel is now generalised on such clusters. More in-terestingly, Campidanese, while accepting word-initial sC clusters, displays a phonological process of vowel prosthesis: a vowel is inserted at word-boundaries when a final coda precedes the cluster. I will focus on this process, to argue for a heterosyllabic analysis of sC clusters for Sardinian.