Anglophone children in Grades 2 and 5 who attended an intensive French immersion program were examined for linguistic and metalinguistic ability in English and French. Measures of linguistic proficiency (vocabulary and grammatical knowledge) were consistently higher in English and remained so even after 5 years of immersion education in French. Measures of metalinguistic ability (letter fluency and ignoring semantic anomalies in sentence judgments) in French improved significantly over the two grades studied and closed the gap (letter fluency) or caught up with (sentence judgments) similar performance in English. This dissociation between developmental trajectories for linguistic and metalinguistic development is exactly the pattern expected for fully bilingual children, endorsing immersion education as a route to bilingualism. (Contains 1 table, 2 figures and 2 notes.)