Fiber matrix adhesion was promoted by hybrid fiber composite surface modifications using an alkaline treatment. However, it was found that the resulting strength and stiffness of the composite. The elastic modulus of the composite did not improve with the fiber surface modification. A notable disadvantage of natural fibers is their polarity which makes it incompatible with hydrophobic matrix. The defect can be remedied by chemical modification of fiber so as to make it less hydrophilic. The present contribution reports effects of fiber content and length on the mechanical properties of the banana and kenaf hybrid reinforced polymer composites. The composites prepared with alkali-treated banana and kenaf fibers were used for comparison of the properties. The fibers were subjected to 20 % of sodium hydroxide (NaOH) solution for 6 h. Besides, the fractured surfaces of composite specimen were investigated using scanning electron microscopic (SEM). An improvement in strength, stiffness and toughness was achieved by treating the fibers using NaOH solution. Morphological and structural changes were investigated using scanning electron Microscopic.