A field trial was conducted at the Al-Rabee center, Baghdad to in vestigate the influence of primary tillage on practical productivity, fuel consumption and cost for machinery units. The experiment includes the effect of two seasons and three plowing including primary tillage system (mold board , chisel   and disk plows).Randomized complete block design with three replications and LSD (0.05) was used to compare the means of treatments at 0.05.  The experiment results showed the following:- Chisel plow indicated significant superiority upon moldboard and disk plows in achieving higher practical productivity combined with lower total cost.