The aim of the study was to evaluate the possible effect of dried Thyme (Thymbra spicata L.) pulp (DTP) on first-cut meadow grass (Poa trivialis L.) and alfalfa (Medicago sativa L.) silage fermantation parameters and in vitro organic matter digestility. Experimental silage consisted of four replicates for each silage group (Grass, (G) and Alfalfa (L), respectively). Each silages groups were supplemented with DTP at 0, 0.5, 1.0, 3.0, and 5.0% level, respectively. The silos were stored for 60 d at room temperature (about 22(circle)C). Results showed that silages added with DTP had higher amounts of NDF, acetic acid and propionic acid whlist lower amounts of lactic acid and NH3N-TN compared to those of control (P<0.001). DTP significantly reduced microbial load of silage opened at 60 days without changing lactobacilli (P<0.001). It was concluded that the reducing in the load of undesirable microorganisms (Enterobacter, yeast and mould) without causing a decline in the number of lactobacilli could be provided significantly advantages in terms of improving the aerobic stability of the silages.