The article presents the results of internal consistency and internal structure analysis on a sampleof 184 subjects of the four most widely used questionnaires of tolerance / intolerance to ambiguity: the Intolerance to Ambiguity Scale (IAS) by S. Badner, Multiple Stimulus Types Ambiguity Tolerance Scale (MSTAT-I and MSTAT-II) D. McLane and the Tolerance-intolerance of ambiguity new questionnaire (TAN) by T. V. Kornilova. The IAS subscales showed low internal consistency, the Tolerance-intolerance of ambiguity new questionnaire scale showed satisfactory internal consistency and the MSTAT-I and MSTAT-II scales showed high internal consistency. Confirmatory factor analysis confirmed the five-factor model of MSTAT-I, the other models were not confirmed on our data. Exploratory factor analysis revealed unsatisfactory internal structure of the IAS, TAN, MSTAT-II. The results of the study are discussed.