The generation and application of probabilistic models are required to make assertive decisions based on data associated with user access and service times in various organizations. The objective was to analyze the waiting line system of the central library of a university, using parameters designed to measure its performance. The methodology included quantitative techniques focused on a cross-sectional design. The information was collected with an observation grid and counting the number of students who entered the library in 10 minute periods to carry out consultation activities. Probability models were adjusted with the data to describe the operation of the system. The results showed that it operated stably, with short waiting times and relevant service times. It was concluded that the analyzed library system achieved a high percentage (89.06%) of use by the students during the observed hours.