A mixture of NaOH and Na 2 SO 3 was used in modification of banana stem fibers (BSF). Unidirectional BSF reinforced natural rubber (NR) lamina composites were made using compression moulding method. The results of the tensile loading in 0˚, 45˚ and 90˚ to the fiber directions of the composite with fiber mass fraction of 30% were studied. Surface modification of the BSF with a mixture of 4% NaOH and 2% Na 2 SO 3 increased the tensile strength and elastic modulus of the composite to 4.03 MPa and 147.34 MPa respectively from 3.12 MPa and 84.30 MPa of the untreated. Variation in properties due to fiber orintations was observed indicating a higher value of properties in the 0 o fiber orientation than in 45˚ and 90˚ directions. The result of scanning electron microscope (SEM) micrographs of the surfaces of the fibers indicted an improvement in bonding of the fiber bundles prior to lamination with natural rubber as a result of surface treatment which resulted in its higher tensile strength.