The aim of this research is to determine the optimum factors affecting mechanical planting of coated marjoram seeds. The studied factor is four forward speed levels. The main results of this study can be summarized as follows: The maximum marjoram seeding rate of 3.50 kg/fad., was obtained at metering-device speed of 20 rpm. while, the minimum seeding rate of 2.30 kg/fad., was obtained at metering-device speed of 60 rpm. The maximum plant-emergency of 93.6% was obtained at forward speed of 1.82 km/hr. While, the minimum plant-emergence of 82.3% was obtained at forward speed of 4.79 km/hr. By increasing forward speed from 1.82 to 4.79 km/hr., the total crop-yield decreased from 3200 to 2400 kg/fad. Also the minimum production-cost of 26 LE/ton was obtained using forward speed of 4.79 km/hr.