INTRODUCTION. Patellar tendon (PT) autograft is an excellent choice repairing anterior cruciate ligament (ACL) ruptures. Published studies testing the biomechanical characteristics after plasty usually refer to grafts with 10mm wide. The thickness of PT and geometry of the patella have been overlooked. The purpose of this study was to understand the geometry of PT and patella in our population, regarding their use in Bone - Patellar Tendon - Bone (BTB) technique, in order to evaluate their biomechanical efficiency and study their relationship with anthropometric parameters. MATERIAL. 100 individuals (50/50) who underwent knee MRI (3-Tesla). Ages between 18–65years. METHODS. Retrospective study. Standardized protocol for measuring the PT and patella based in MRI images. Interview to obtain personal data. Statistical analysis using SPSS®. RESULTS. Sample (mean ±SD): age 41 ±14years, weight 73 ±12kg, height 167 ±10cm, BMI 26,04 ±4,13; length PT/patella −41,3 ±6,1mm/29,6 ±4,2 mm, width PT/patella −25,3 ±3,2mm/43,4 ±4,14mm; thickness PT −3,79 ±1,01mm/22,8 ±2,2mm; Men have thicker and wider patella and PT than women (p<0.001). The patella is also longer in males (p<0.001). There is statistical significant relationship between weight and height to width, thickness and length of PT and patella (p<0.01). Body Mass Index (BMI) doesn't have statistical correlation with geometry of the PT and patella. DISCUSSION. The PT remains as an excellent option in ACL repair. The anatomy and quality of the graft are essential to achieving good functional results. The choice of middle third tendon to the BTB plasty does not always correspond to the 10mm width, as used in most biomechanical tests. Also patellar integrity can be at risk (when collecting the bone block) if patella geometry is not considered. To our knowledge, there is only one similar study in literature, preformed in Asian individuals. CONCLUSION. Preoperatively accessing the geometry of Patella and PT can be crucial in obtaining efficient grafts and decreasing morbidity over the extensor mechanism