The objective of the present investigation was to modify some parts of the local watermelon seeds extraction machine, where the developed machine can be used with the extraction of watermelon seeds and chop the fodder beet. The developed machine has been evaluated under three beet moisture contents of 86.2, 81.3 and 76.85 %, four rotor speeds of 325, 405,460 and 540 rpm and three number of knives rows of 2, 3 and 4 rows. The evaluation was based on the following parameters: The chopping sizes, machine productivity, consumed energy, and chopping cost. The results recommended operating the machine at rotor speed of 540 rpm, number of knives rows of 4 row and beet moisture contents of 86.2 % to maximum values of beet sizes -1), with consumed energy of 1.08 kW.h ton-1 and the minimum chopping cost of 20.49 L.E ton-1.