The present study aimed to evaluate the effect of some engineering factors involved in processes of corn and wheat seed coating. The engineering factors were speed of the coating pan, diameter of the spinner disk, slope of the coating pan and speed of the spinner disk. The results revealed that, the coating efficiency increased as the slope of coating pan increased up to 27.66 × 10^-3 rad., then tends to decrease with higher angle of slope. Also, a significant coefficient of variation was found only with corn seeds. The coating efficiency increased as rotating pan speed increased up to 0.056 m/s, then tends to decrease with higher rates of speed. The coating efficiency increased as disc diameter and/or speed increased. The study can be concluded that the effect of the spinning disk properties as its diameter or speed is the significant effect on the coating seeds compared with the coating pan as its slope angle or speed.