A number of studies in the field of bilingualism and early childhood education have been made. Very few studies, from the ones I found, focus specifically on using music activities with the bilingual children, which raises interest for this particular research. Being a teacher of music myself it made me especially interested in such kind of research. The study may lead to a better understanding of influence of music lessons on extending of vocabulary of children living in mixed communicative environment in Oslo. The study was conducted for 16 bilingual (Norwegian-Russian) children 4-5 years old who are attending Russian Sunday Pre-School once a week and where I work as a music teacher. All children had at least one of the parents with Russian as a native language. It is worth to note that my study task can be characterized as qualitative research rather than quantitative (however, with using quantitative procedures). The main purpose was not to estimate “exactly” Russian language development level for children but to find (if there any) differences between first (pre-test) and the second (post-test) vocabulary estimations. Music lessons have been conducted between those assessments. However, due to the restricted amount of time for the whole research I realized that a significant change in such a stable characteristic as development of vocabulary for the selected children would be difficult to expect.