The aim of this study is to determine the effects of density and melamine rate on thickness swelling, moisture resistance, modulus of elasticity in bending, bending strength and tensile strength of Oriented Strand Board. For this purpose, Oriented Strand Board panels were produced at three different density (550 - 570 - 590 kg.m-3 in size of 2440 x 1220 x 11 mm) and at five different mixture ratio of melamine in urea formaldehyde resin (0% - 2.5% - 5% - 15% - 20%). Urea formaldehyde and melamine urea formaldehyde included 65% solid content was used of 9.5% ratio relatively dry wood chip weight. At the process of Oriented Strand Board panels, Black pine (Pinus nigra), Scots pine (Pinus sylvestris) and Fir wood (Abies nordmanniana) chips were used at a rate of 80%, 15%, and 5%, respectively. Obtained results show that a linear correlation between the value of horizontal bending resistance, modulus of elasticity with panel density and melamine amount. It was understood that the values of longitudinal bending resistance did not show a direct increasing or decreasing in melamine amount and value of density. As it is seen that the values of longitudinal modulus of elasticity increases in proportion with the increase in the density. In perpendicular tensile strength to the surface; it is seen that values of all glue groups and density values which are intended by the standard for density values are covered. As melamine reinforcement ratio increases, average values of free formaldehyde decrease. It was determined that there was no direct correlation between the value of thickness swelling and panel density, and it had a correlation with used glue type.