The purpose of the study is to investigate into professional knowledge of the bilingual teachers, compared to monolingual, and what benefits they give to pre-school. Qualitative method was used to get an understanding of informant´s perspective on bilingual teachers. The informants believe that bilingual teachers are able to understand all the children. A bilingual teacher can make the children feel secure. If one has a positive attitude toward bilingualism, the bilingual children also show a positive attitude that in turn contributes to learning and development of the language.