The mandible plays a critical role in vital human functions as eating,speaking and breathing. No other bone in the body has such a distinctiveshape and function. Because of its prominence in the facial structure, themandible is highly prone to fractures.Aim: The aim of this study is to evaluate the biomechanical behavior ofthree different fixation systems for fractures of the body of the mandibleunder bench top conditions that resemble clinical function.This study included 15 hemi mandibles taken from similar sheep (sameweight, fed on same diet, collected from the same abattoir and slaughteredsimilarly).All the biomechanical experiments had been done in the laboratory ofmechanics department in faculty of engineering, Cairo University.The loads were applied until the 2 bone segments were separated from eachother with concomitant twisting of plates which resulted in end point offailure of the system used.ANOVA test showed that there was a statistically significant differenceamong the three groups (P-value < 0.001).Conclusion: The 2.3 plate achieved highest biomechanical results in regards of yield loadand stiffness as compared to 2.0 and 3D strut plate techniques, while the 3Dstrut plate achieved highest biomechanical results in regards of displacementas compared to 2.0 and 2.3 plate techniques.