This study argues that both Shanghai and Taiwanese have a metrical system, that compound stress is left-headed in Shanghai and right-headed in Taiwanese and that a tonal domain is a metrical domain. It predicts tonal domains better than previous studies and explains some asymmetries between Shanghai and Taiwanese. It also supports the view that metrical structure can be determined in languages that lack data on phonetic stress. In addition, it shows that compound stress is not universal, contrary to the proposal of Cinque 1993. Finally, this study has implications for the theory of prosodic structure.