The aim of this study was to examine the articulation characteristics of preschool children in the bilingual or monolingual environment. Subjects included 23 children of 4 to 6 years old in the bilingual environment, and 19 children of monolingual environment. Their speech was evaluated in terms of articulation correctness and intelligibility by the author and a speech therapist. Results showed as the following: First, there were some significant differences between bilingual and monolingual children in the percentage of consonants correctly articulated. But there was no significant difference between their language environment or ages in the percentage of vowels correctly articulated. Second, there were some significant differences between the bilingual and monolingual children in the intelligibility of word articulation. Also, there were some significant differences between the two language groups in the sentence intelligibility. There was a high positive correlation between the word and sentence intelligibility.