The aim of this research is to develop environmentally friendly, lightweight composites using cow horn, as filler in Acrylonitrile-Butadiene-Styrene (ABS) polymers; to determine the tensile strength and tensile modulus properties of the cow horn-residue polymer composite, to find if there is any new improvement over the properties of the starting polymer and to determine the morphology and elemental composition of the composites. Cow horn was collected from the surroundings of Ekwulumili in Nnewi-South L.G.A and Nnewi-North both in Anambra State, Eastern Nigeria where they have been dumped after usage. The research was carried-out at JUNENG NIG LIMITED Enugu, Civil Engineering Department Laboratory University of Nigeria and Chemical Engineering Department Laboratory Ahmadu Bello University (ABU), Nigeria; between May 2016 and August 2018. The cow-horn were grand into power and incorporated into the virgin thermoplastic polymers as filler at varied levels of 3%, 6%, 9%, 12% and 15%. The virgin thermoplastic polymers were used as the Control in the study. The tensile strength and modulus of elasticity property of the composites produced were determined using American standard for Testing and Materials (ASTM), Standard Testing Methods; Scanning Electron Microscopy (SEM) was used to determine morphology while Energy Dispersive Spectroscopy (EDS) was used to determine the elemental composition of the composites. The results generally showed significant improvements in tensile strength and tensile modulus of the blend ABS cow horn filler composites which were influenced by the amount of filler in the composites. ABS matrix loaded with 3% MoE of 516.72 MPa (Mega Pascal), ABS 6% MoE of 335.73 MPa, ABS matrix loaded with 9% of cow horn had MoE of 463.30 MPa, ABS matrix loaded with 12% of cow horn had MoE value of 209.24 MPa and ABS matrix loaded with 15% of cow horn had MoE of 236.36 MPa. MoE of 160.68 MPa for pure ABS matrix. The values obtained for tensile strength are 15.62 MPa, 9.05 MPa, 13.98 MPa, 10.69 MPa, 5.76 MPa and 6.58 MPa for 3%, 6%, 9%, 12%, 15% of cow horn filler and pure ABS matrix respectively. Scanning electron microscopy (SEM) was carried out on the samples using imageJ software to estimate the average particle size of the polymer cow horn. The micrograph reveals some agglomeration bulk and voids at the edges of the particles of the filler material with the polymer. The elemental compositional analysis, using Energy Dispersive Spectroscopy (EDS) has sample contains C and N as a major element present and others as trace; Fe, Na, Ag, Cu, Ti, Al, Mg, P, Zn, Si and S. This study has proven that combinations of lost-cost cow horn -residue filler reinforced with thermoplastic polymer composites are gaining significant roles in building and automobile industries, and other consumer applications. Also, would serve as a means of turning waste to wealth by utilizing agro-waste products in developing low cost polymer composites to serve a number of interesting applications.