Composite parts, used in transportation industries, are manufactured using VARTM (Vacuum Assisted Resin Transfer Molding) and glass fiber non-woven mats that are optimized for impregnation, fiber volume fraction (Vf), and composite properties. However, such optimized non-woven mats are commercially not available for natural fibers such as hemp and flax. Fahimian (2013) has developed the knowledge on the effect of areal density (weight per unit area), needle punching used to bind the fibers together, and the pressure applied during manufacturing, on composite properties. Similar studies on flax fibers is not available. Such studies on Cattail fibers, with comparable properties and abundance, are lacking. Hence, the goal of this thesis to generate this knowledge and do a comparative evaluation of flax, cattail, and hemp fibers and their composites. The mat permeability as well as tensile strength and modulus of needle-punched (0-72P) flax composites, manufactured using VARTM pressure as well as compression molding pressures (subsequent to VARTM molding), were measured and evaluated. Similar studies were repeated on 50% Flax-50% hemp fiber mat. Cattail fibers were extracted from cattail leaf using alkali retting, characterized for properties, and used to manufacture 0-P mat. This was subsequently used to test for permeability as well as manufacture composites for mechanical testing. The results from these studies as well as that for hemp fiber (generated by Fahimian (2013)) were used in comparative evaluation of the three fibers as reinforcement in composites. It was found that the Vf of flax mats changes with punch density that affects the permeability. Vf in flax mat composite dictates the modulus and strength which is a function of consolidation behavior that varies with punch density and pressure. Despite having similar tensile strength in all three fibers, cattail fibers possess higher specific strength than flax and hemp due to lower density values of cattail fiber; however, modulus and specific modulus increases as follows (Eflax< Ecattail<Ehemp); it should be noted that the weight of the composite part decreases with increase in specific properties of the fiber. The transverse permeability of cattail fiber mat is the highest, followed by hemp fiber mat and the flax fiber mat’s permeability was the least. At VARTM pressure (101 kPa) the properties of composites with three fibers are similar.