Abstract. Introduction: periapical lesions are an important finding in endodontic practice because of the information they provide for the diagnosis and treatment plan. The aim of this research was to describe the radiographic findings of periapical lesions in the clinical histories of patients treated endodontically.  Methods: this descriptive study measured size, location, enlargement of the periodontal ligament, lamina dura, and bone loss of apical lesions and treated teeth. The study included 576 xrays obtained between 2003 and 2007, taking defined selection criteria into account. A format was designed and the x-rays were standardized using a calibrated digital reader. Statistical analysis was performed using the STATA program.  Results: the average age was 32.1 ± 14.6 years. The x-rays related to female patients in 59.4% of cases and males in 40.6% of cases; 38% presented large lesions (> 7 mm). Bone loss was detectable in 18.2% of cases. Finally, the lamina dura had greatest continuity in the range of 8 to 10 mm with 37.5%. Conclusions: the results suggest that the characteristics of the periapical lesions were consistent with other findings described in the literature. As well as the x-rays, other findings must be taken into account for correctdiagnosis and treatment.