The objective of this research was to evaluate the influences of the board density on the mechanical properties and to verify the correlations levels between the variables studied. They were manufactured panels with the nominal density of 0,60; 0,70; 0,80 and 0,90 g/cm³, using particles of Pinus spp collected at the particleboad industry and urea-formaldehyde resin. The average values obtained for MOE and MOR in static bending, internal bond and compression parallel to grain become higher for as the board density increases. The increase in board density near of 0,80 g/cm³, results in proportionally higher values of mechanical properties. This results indicate the possibility to manufacture the particleboard with density above to 0,80 g/cm³ for specific applications that required high mechanical strength. With the exception of the internal bond, the linear relation between board density and dependents variables – MOE and MOR in the static bending and MOR in the parallel compression to grain, showed high coefficient of determination indicating the possibility of predicting these properties basing on the board density