Resumo. The shear stress as a function of the inclination of the wood fibers were determined through experimental tests. The test specimens were obtained from a sample of wood beams 12 Eucalyptus saligna , following the requirements of NBR 7190. They were made with variable slope fiber (0 º, 15 º, 30 º, 45 º, 60 º, 75 º, 90 º). Through statistical analysis it was possible to estimate the parameters of variability of shear stress with the slope of the wood fibers. The shear stresses were corrected to standard moisture of 12%. With robust statistical analysis of the data set, it was possible to define the empirical equations that best define this phenomenon. Equations proposed in the literature by Hankinson, Karlsen, DIN 1052 and Keylwerth, the formulation prescribed by DIN 1052, with necessary modifications, has a better fit to the experimental results.