As part of the THIMP project (Telephony for Hearing- IMpaired People), we aim at automatically analyzing Cued Speech (1) and translating it into oral spoken language. This work focuses on vowel classification and will be part of this transcoding process as a preprocessing step of the input data analysis. Its objective is to identify vowels produced by a speaker pronouncing and coding in Cued Speech a set of French sentences, knowing: - The Cued Speech Hand Placement, - The analysis of defined Labial Parameters. Here, we will show that the crossing of these two sources of information allows to automatically identify vowels. These results have to be compared to performances of hearing- impaired people in perception of Cued Speech.