Objectives: The purpose of this study was to analyse radicular dental permeability when using rotatory instrumentation technique. Methods: Twenty-four monoradicular mandibular teeth were selected and had their crowns removed. These speciemens were divided in two experimental groups: GI (n=10): the root canals were instrumented with flexofile manual files (Maillefer®) until # 35 and GII (n=10): the root canals were prepared with K3 rotatory instruments (SybronEndo™) until # 35/.2. The root canals were instrumented with a solution of 1% sodium hypochlorite and Endo-PTC® cream and at the end irrigated with EDTA-T solution. The control group (n=4): the root canals were accessed, not being instrumented. Afterwards, the specimens were externally impermeabilized and immersed in dye. After this period, the teeth were washed and worn in a mesio-distal direction. The images were digitized and they were evaluated by means of specific software that analysed the blue color intensity in the different radicular thirds. Results: The results were statistically evaluated by EPI INFO program, which did not present estatistically significant differences among the experimental groups, independently of the analyzed third. Conclusion: The authors conclued that the rotatary instrumentation technique did not influence in radicular permeability.