One of the most important indicators for using wooden materials as a building material is safety stress (SS). Site index is also an essential criterion for construction materials. This research was planned with the aim to reveal the relationship between safety stress and site index classes (I, II, III) of red pine wood, which is an important tree species of Turkey and the Mediterranean basin. Also, the safety coefficient was calculated. The safety stress tests for compression, bending, and tensile, tensile perpendicular to fibers, cleavage, and shearing strengths were calculated as 9.2, 9.7, 8.9, 0.35, 0.10, and 1.4 N/mm2, respectively. The statistical analyses indicated that the site index difference had a significant effect on the safety stress in red pine wood as mentioned above. Again, the safety coefficient was calculated as 5.27 for red pine wood. In addition, it was determined that the safety stress values of red pine wood provided the desired lower limit values according to the standard (TS 647 and EN 1995-1-1), excluding class I. As a result of the regression and correlation analyses, the presence of a moderately increasing linear relationship (R2 values equal to 0.41-0.68) was found between the density and safety stress values for all site indexes.