This investigation has established the Possibility of improving the values of physical-(Water absorption and cross-swelling after 2, 24, and 48 hours) and mechanical Properties (binding strength and cross-tensile strength) of Medium Density Fiber board (MDF) from Cotton Stems (Gossypium sp.) bonded with Urea formaldehyde    resin (UF) by adding Parafin emulsion (0.5 % or 1 % to the dry weight of the fibers) when producing the Medium Density Fiber board (MDF) to reach the mean of values for the physical-(Water absorption and cross-swelling after 2, 24, and 48 hours) and mechanical Properties (binding strength and cross-tensile strength) of Medium Density Fiber board (MDF) in the European Standard.