This study is focused on predicting the fatigue life expectancy of Girth gear-pinion assembly used in cement industries. Gear design and modeling was carried out using a CAD package and analysis was done using finite element analysis software, ANSYS. AISI 4135-low alloy steel material properties are considered and linear elastic finite element analysis and fatigue life analysis were carried out. The variable amplitude load is applied to simulate the real time loading of the gear-pinion assembly. Rainflow cycle counting algorithm and Minars linear damage rule is employed to predict the fatigue life. The critical stress and the corresponding deformation are discussed in the results. Finally the life expectancy of the girth gear and pinion assembly is estimated which would be useful for the periodical maintenance of the gear assembly.