The purpose of this paper is to identify the factors that influence the acceptance and use of mobile banking among users in Medellín (Colombia). The factors we propose are built upon on seven constructs (customer service and support, perceived attitude, perceived usefulness, ease of use, perceived trust, intention to use, and perceived security), which were developed based on the Technology Acceptance Model (TAM) and the literature. We collected the data from 220 questionnaires self-administered by mobile banking users in Medellín. Subsequently, we conducted a confirmatory factor analysis to determine the correlation between the set of observed variables and the constructs defined in the proposed acceptance model. We empirically conclude that the use of mobile banking among the population under study is mainly influenced by users' perceived usefulness, perceived trust, and ease of use. The results show a strong correlation between perceived trust and perceived security and between perceived usefulness and intention to use.