The aim of this research is to study the factors affecting a mechanical coating of fennel seeds. These factors are coating speed, temperature and time, and seed batch. The main results in this study were: The maximum fennel-seed germinations of 55.9, 61.2 and 42.9 % were obtained by using coating-unit speed of 28 rpm, coating time of 15 minute, coating temperature of 30 C o and coating with "Fe + Zn", "Fe + Zn + Cersan" and clay respectively. Meanwhile, the minimum fennel-seed germinations of 3.5, 4.5 and 1.5 % were obtained by using coating-unit speed of 36 rpm, coating time of 65 minute, coating temperature of 70 C o and coating with the same constitutions respectively. The maximum machine capacity of coated fennel-seeds of 4.8 kg/h was obtained using seeds-batch mass of 2.5 kg and coating-unit speed of 36 rpm. Meanwhile, the minimum machine capacity of coated fennel-seeds of 0.65 kg/h was obtained using seeds-batch mass of 0.5 kg and coating-unit speed of 20 rpm. The operation and production costs at optimum parameters (batch mass of 2.5 kg, coating-unit speed of 28 rpm, coating temperature of 30 0 C, coating time of 15 minutes and coating with "Fe + Zn + Cersan") were 10.63 L. E./h and 3037 L.E./ton respectively.