The use of mother tongue in teaching in a multilingual setting affects the way pupils learn. A melting pot and the educational center of the North, Baguio City, Philippines demands teaching strategies that not only adapt to the interplay of the different cultures and languages but give importance to them, too. Specifically, this paper analyzed the strategies of teachers in implementing Mother Tongue-Based Instruction in a Multilingual Classroom and identified some problems that teachers encounter in implementing them. The study used qualitative analysis with interview as the main data gathering tool. The respondents were teachers purposively selected from the suggested pilot schools of Mother Tongue-Based Multilingual Education (MTB-MLE) in Baguio City. From the phenomenological analysis of the data, the findings showed that the teachers used strategies such as translation of target language to mother tongue, utilization of multilingual teaching, utilization of lingua-franca, improvization of instructional materials written in mother tongue, remediation of instruction, and utilization of literary piece written in mother tongue as motivation. Some problems encountered by the teachers in implementing mother tongue-based instruction include absence of books written in mother tongue, lack of vocabulary, and lack of teacher-training. Nevertheless, the study indicated that major attention and effort are still necessary to be given to the approach.