Introduction and objectives: One of the most widely used scales to assess anxiety is the BAI (Beck Anxiety Inventory) that has shown adequate psychometric properties; however, there is no consensus on its internal structure. This work aimed to study the internal structure of the BAI using Confirmatory Factor Analysis (AFC) for the first time in Mexico, as well as the goodness of the items that make it up and its internal consistency. In addition, descriptive data of anxiety levels in the general population of Michoacan (Mexico) are presented. Material and methods: The BAI was administered and the sociodemographic data (sex, age, marital status, and education) were requested from 1,245 adults. First, an Exploratory Factor Analysis (EFA) was carried out with half the sample. Using the second half of the sample, the factorial models obtained in previous Mexican studies, the single factor solution and the model obtained in the AFE were tested through a CFA. Results: A high internal consistency of the total scale was observed (alpha = .911); however, no model of those tested in the CFA was satisfactory. Conclusions: It can be concluded that the BAI, despite showing an unstable internal structure, can adequately assess the presence of anxiety symptoms in the general population of Michoacan (Mexico). It is important to note that up to 24.9% of the sample presented moderate or severe anxiety levels. (C) 2020 Sociedad Espanola para el Estudio de la Ansiedad y el Estres - SEAS. Published by Elsevier Espana, S.L.U. All rights reserved.