The phonetic inventories of 122 typically developing Cantonese-speaking children, aged from 0;10 to 4;7, were examined in terms of feature distinctions. The applicability of Dinnsen. Chin, Elbert and Powell's implicational feature hierarchy to these data was investigated. Results show that modifications to the hierarchy are necessary for the Cantonese phonetic system. A revised hierarchy for Cantonese is proposed. Differences between this proposal and the original work are discussed. The implicational nature of the proposed hierarchy was also tested on longitudinal data from ten children (aged from 0;10 to 3;5 at the beginning of the study) over a 1 year period. The proposed hierarchy successfully predicted the route of sound change of these inventories. Implications for further research on feature development are discussed.