The problem of a person's attitude to uncertainty is one of the most topical issues of our time. In this regard, it is important to find correct methods for detecting and measuring this construct. The most common method for assessing tolerance and intolerance to ambiguity are questionnaires. One of such questionnaires is the Measurement of Ambiguity Tolerance (MAT-50) developed in 1975 by R. Norton. Despite the fact that the original scale has high psychometric properties and allows to assess tolerance to ambiguity in a wide range of situations, it has not yet been adapted on a Russian sample. The aim of this paper is to assess the internal consistency and internal structure of the MAT-50. This article presents the first stage of adaptation of R. Norton's Measurement of Ambiguity Tolerance (MAT-50) on the Russian-language sample, namely, the analysis of the internal structure of the questionnaire. The test-retest reliability and convergent validity were also assessed. It was shown on a sample of 843 subjects, that the scale has high internal consistency. The result shows four of the eight subscales showed a good level of internal consistency. The confirmatory factor analysis didn’t confirm the original eight-factor structure. The principal component analysis revealed an eight-factor solution, which explained 41.9% of the variance. Four factors could be well interpreted according to the following subscales: Public Image, Social, Problem-solving, Habits. Adap­ta­tion of the measurement has not yet been completed, further work will be aimed at clarifying the internal structure of the scale, as well as assessing the validity and retest reliability. Adaptation of the MAT-50 on the Russian sample could significantly supplement and expand the data obtained using the existing in Russia measurement of tolerance to ambiguity.