The perception of Brazilian Portuguese (BP) mid vowels is mainly investigated by foreign researchers who work with learners of Brazilian Portuguese, native speakers of English or Spanish. In Brazil, this field has been poorly explored. This work contributes to filling this gap by investigating the perception of two Brazilian Portuguese minimal vowel pairs in the group of 103 native Russian speakers and nine French speakers, most of them residing in Brazil. The test has been designed to evaluate the perception of the mid high and low front vowels [e] - [ε], and the mid high and low back vowels [o] - [ɔ]. The test is conducted online and includes 30 trials distributed in three types of tasks: image identification (8 trials), vowel identification (4) and word discrimination (18). It also contains a short sociolinguistic questionnaire. Our findings indicate that native Russian speakers do not differentiate the Brazilian Portuguese mid vowels very well: the mean percentage of the correct answers in the Russophone group was 68%, while in the French group it was 87% and in the Brazilian control group 99%. No correlation was found between the percentage of correct answers and residence time in Brazil or type of language instruction. As next steps, we plan to investigate the differentiation of the Brazilian Portuguese open and close mid vowels by Russophones at the level of production. We also intend to create a training corpus and develop strategies for perception training of the Brazilian Portuguese mid vowels, monitoring their efficiency at different time points.