The Russian version of the matrix sentence test (RUMatrix test) has been shown to be suitable for accurate assessment of speech intelligibility in adults. Objective. To approve the RUMatrix for measurements in children and to evaluate its simplified version (Simplified RUMatrix). Participants and methods. 20 normal-hearing adults and 81 normal-hearing children aged from 5 to 10 years were involved into the study. Both versions of the test were developed by the University of Oldenburg, Germany. The tests contain syntactically homogeneous, semantically unpredictable sentences/phrases presented under the background noise. Each test list is composed of 20 sentences of 5 words for RUMatrix and of 14 speech phrases of 3 words for Simplified RUMatrix. Results. A limitation in the use of the RUMatrix test in children under 10 years of age has been revealed. Evaluation of Simplified RUMatrix test in adults confirmed the perceptual homogeneity of the test list. The results of the RUMatrix test and the Simplified RUMatrix test in children were lower than in adults; they were improving with age and reach adult values by 10 years. One training track of Simplified RUMatrix test should be carried out before the assessment. Conclusions. The RUMatrix can be used for children of 10 years and older. The normative data of Simplified RUMatrix both for adults and children of the different ages have been obtained.