Abstract: In this paper we present experiments we perform in order to recognize Arabic isolated words. Our recognition system is based on the combination of the vector quantization technique at the acoustical level and the Markovian modelling. The Hidden Markov Models (HMMs) are widely used in number of practical applications and especially suitable in speech recognition because of their ability to handle the variability of the speech signal. In our system, a word is analysed and represented as a set of acoustical vectors then transformed into a symbolic sequence, using the vector quantizer. This observation sequence is compared to the reference Markov models. The word associated to the model who obtained the highest score is declared the recognized word.