The coconut palm tree leaf sheath fibers were analyzed by FTIR spectral analysis, Chemical, X-ray and thermo gravimetric methods to assess their suitability as reinforcements in the preparation of green composites. The morphology of the untreated and alkali treated fibers was studied by scanning electron microscopic method. The FTIR and chemical analyses indicated lowering of hemi-cellulose content by alkali treatment of the fibers. The X-ray diffraction revealed an increase in crystallinity of the fibers on alkali treatment. The thermal stability of the fibers was found to increase slightly by alkali treatment. The tensile properties of these fibers increased on alkali treatment. The mechanical and other physical properties indicated that these fibers were suitable as reinforcements for making the green composites.