The main objective of this research was to fabricate and evaluate a new design of tractor front mounted mower to improve its performance, reduce harvesting costs (operation cost and losses cost) and to minimize energy consumption. The machine was locally fabricated to suit the small and medium Egyptian farmers, the performance of the developed machine was evaluated under four different tractor forward speeds (2.5, 3.5, 4.5 and 5.5 km/h) and four different conveyor belt speeds (1, 1.2, 1.4 and 1.6 m/sec) at 45º of conveyor belt angle with horizontal level and constant speed of the P.T.O at 540 rpm. The traditional mower was evaluated to compare its performance with the developed mower at the same previous four forward speeds, also the same conveyor belt speeds with conveyor chain in the other front mower and used tilting angle of 90º with vertical level. The maximum effective field capacity was 1.34 fed/h, the minimum total grain losses, operating cost and specific energy consumed were 0.8%, 61.5 L.E/fed and 9.5 kW.h/fed compared to 1.04 fed/h, 1.5%, 80 L.E/fed and 13 kW.h/fed for traditional machine at the optimum operating parameters of 4.5 km/h forward speed, conveyor belt, chain speed 1.6 m/s and conveyor belt, chain angle 45, 90º respectively. The cutting efficiencies for the developed and traditional machine were acceptable.