Introduccion y Objetivo: Varias sustancias y mecanismos se usan en endodoncia para la desinfeccion del conducto radicular. El objetivo de este estudio fue comparar la eficacia del hipoclorito de sodio al 5.25% y el Laser Diodo para desinfectar conductos radiculares contaminados con Enterococus faecalis. Materiales y Metodos: Cuarenta dientes humanos unirradiculares intactos extraidos fueron preparados utilizando una tecnica corono apical, luego de la conformacion fueron esterilizados en autoclave. Todos los conductos se infectaron con Enterococcus faecalis, se dejaron en camara humeda durante 7 dias y se dividieron de forma aleatoria: Grupo I: 16 dientes que fueron infectados y descontaminados NaOCl al 5.25%. Grupo II: 16 dientes que fueron infectados y descontaminados con solucion salina y Laser Diodo. Se hicieron cortes a 1, 2 y 3 micras desde la pared interna del conducto hacia la superficie externa del diente; los cortes fueron tenidos con tincion Gram para tejidos y la presencia o ausencia de Entorococcus faecalis fue examinado bajo microscopio de luz. Resultados: Con la prueba de Chi cuadrado de Pearson se comparo el porcentaje de desinfeccion entre NaOCl al 5.25% y el Laser Diodo y no se encontraron diferencias estadisticamente significativas (valor p = 0.352); sin embargo el grupo del hipoclorito de sodio presento un mejor comportamiento en la desinfeccion (81.0%) comparado con el laser (75.0%). Conclusion: No se encuentra diferencia entre la utilizacion del Laser Diodo y el NaOCl 5.25%. Abstract Introduction and Objective: Several substances and mechanisms used in endodontics for the disinfection of root canal. The aim of this study was to compare the effectiveness of sodium hypochlorite to 5.25% and Laser Diode for disinfecting root canals contaminated with Enterococus faecalis. Materials and Methods: Forty unirradiculares intact human teeth extracted were prepared using a technique apical crown, after the formation were sterilized in an autoclave. All ducts were infected with Enterococcus faecalis, were placed on moist chamber for 7 days and were divided at random: Group I: 16 teeth were infected and decontaminated NaOCl to 5.25%. Group II: 16 teeth were infected and decontaminated with saline and Laser Diode. There were cuts at 1, 2 and 3 microns from the inner wall of the duct to the outer surface of the tooth; cuts were stained with Gram stain for tissues and the presence or absence of Entorococcus faecalis was examined under light microscopy. Results: With the Chi-square test Pearson compared the percentage of disinfection between NaOCl to 5.25% and Laser Diode and found no statistically significant differences (p-value = 0,352) but the group of sodium hypochlorite presented a better behaviour disinfection (81.0%) compared with the laser (75.0%). Conclusion: There is difference between the use of Laser Diode and NaOCl 5.25%. Key words: Root canal therapy, sodium hypochlorite, enterococcus faecalis, disinfection, laser.