This investigation was carried out in the two successive seasons of 2005/2006 and 2006/2007 to study the favorable months for planting wild mint. The results indicated that plant height, number of tillers plant^-1, number of branches tillers^-1and fresh and dry weights of herb increased during Oct., Nov and Dec months compared with the other planting months. Also, chemical constituent i.e. chlorophyll a, b and total, carotenoids, total soluble carbohydrates concentration and oil yield were increased. On the other hand, delaying the flowering date was recorded in these months. Hence, it may be recommended to cultivate wild mint plants in Oct., Nov. and Dec. months under conditions of Fayoum governorate to obtain economical yield of herb and oil.