This study deals with the effect of matrix material (Isophthallic polyester and Epoxy) on the free vibration characteristics (natural frequency) of Phoenix Sp. fiber reinforced polymer matrix composites. The composite were prepared by varying the fiber length (10, 20 and 30 mm) and fiber volume fraction (10, 20, 30, 40 and 50%) with random fiber orientations using hand layup method followed by compression molding technique. The composite samples with cantilever boundary condition was tested by using the standard experimental setup consisting of fixture, an accelerometer, data acquisition kit and a personal computer to determine their natural frequencies. The results revealed that, the matrix material has significant effect on the natural frequency values, due to the variation in their compatibility with the reinforcing fibers. The composites prepared with epoxy matrix showed good free vibration property than that of the composites prepared with isophthallic polyester resin.