In Foreign language class, Target Language should be the primary vehicle of communication but L1 (first language) has an important role to play in the Foreign language (FL) or Second language (L2) classroom. In Foreign Language Class most of the teachers have been using First Language for a long time and do not question the reasons behind using it. The study focuses on identifying the reasons of using mother tongue, benefits of using it and disadvantages of using it. Qualitative method has been used for data collection. I hope, the result of this study will help the language teachers to know about the reasons of their conscious or unconscious use of L1 use. By knowing the reasons of using first language in Foreign Language classes’ teachers may modify their classroom management to reduce the frequency for first language use and use mother tongue as an essential tool.