A successful endodontic treatment requires knowledge of the internal configuration of dental root canals. Most of the people who live in Yucatan are of Maya origin, characterized by a Mongoloid dental pattern. Because of their ethnicity, variations are expected. The purpose of this investigation is to assess the morphological characteristics and variability of this population. One hundred and five extracted first mandibular premolars of Mexican Maya population were analyzed; the sample was obtained from the Oral Surgery Clinic in the School of Dentistry at the Autonomous University of Yucatan with written informed consent. Analyses were performed by means of Cone Beam Computed Tomography. Vertucci's Type I was the most prevalent configuration with 51.4 %, but 41 cases (39.1 %) presented a radicular groove and a C-shaped canal configuration. Overall, we documented 1, 2, 3, and 4 root canals. Mandibular first premolars are very variable in the Yucatecan population. The variability and frequency of C-shape is similar to mandibular second molars confirming the importance of the ethnic background for the endodontic treatments.