To assess the effect of active dry yeast and chicken and cattle manures on the growth and essential oil content of thyme plant (Thymus vu&raris, L.), two experiments were carried out at Baramoon Experimental Station, Dakahlia Govemorate, Egypt during the two successive seasons 2003/2004 and 2004/2005. Chicken and cattle manure (as rates of 12, 18 and 24 m3/fed.) were added to soil before sowing (during soil preparation). The active dry yeast was applied as foliar spray with four concentrations i.e., 0, 1, 2 and 3 gm/I three times, after one week from transplanting, onemonth later and another one month later. The obtained results revealed that kind of manure caused significant differences on growth characteristics in both two seasons. Chicken manure gave better performance than cattle manure. Active dry yeast increased plant performance in all studied characters. Best growth characteristics were obtained with 24 m3/fed of chicken manure with 3 gm/liter of active dry yeast, at two seasons. Interactions between three factors i.e., kind of manure x levels of manure x active dry yeast levels shown significant differences on results in most treatments.