In Amhara pipe factory it is clearly investigated that, because of the failure of a single spur gear inside the gear box leads the company for a lot of expenses and lose a hundreds of thousands of birr due to the working downtime. The main objective of this thesis is to study the influence of ferrous materials on the bending failure of the spur gear using FEA. The methods used for the study are analytical method and FEA using ANSYS workbench. The type of gear used for the study is spur gear with 10 Kw input power and 940 r.p.m speed. Steel materials AISI316 stainless steel, AISI4340 steel, AISI1040 steels and steel/Aluminum alloy composite are selected for the study. Lewis bending equation is used for analytical bending stress calculation. The bending stress obtained from the analytical calculation due to the tangential load is 8.962MPa. The analytical result are 9.469MPa for AISI316, 9.462MPa for AISI1040 and 9.474 MPa for AISI4340 steel. The simulation result used the equivalent von-misses analysis. The simulation result obtained are 10.708MPa for AISI316, 10.82MPa for AISI1040 steel and 9.1347MPa for AISI4340 steel. The error percentage of the analytical and simulation results are validated. The life and the factor of safety of the materials are calculated in ANSYS workbench. The factor of safety of AISI316 stainless steel is the lowest than two steel materials. Generally, from the study steel/Al composites have high strength to weight ratio than the steel materials. This shows that the influence of ferrous gear materials on bending failure of spur gears. Finally, the study recommends it’s best to replace steel gears into steel/Al alloy composites for best strength to weight ratio and best bending failure of spur gear.