Dried Distillers Grains with Solubles (DDGS) has been investigated for its use as a functional filler in wood particleboards bonded with Melamine Urea Formaldehyde. Both the concentration of the DDGS filler – 5, 10, and 15 wt. % – and the particle size of the filler – 125, 300, and 500 μm – has been considered. It was presumed that the additional protein and fats in the lignocellulosic DDGS would increase strength and water resistance of the particleboards. Chemical analysis, thermogravimetric analysis, and differential scanning calorimetry were used to analyze the DDGS filler. A variety of mechanical tests were performed including: flexural, internal bond, hardness, screw withdrawal, linear expansion, and water absorption. The results show that DDGS bonded to the MUF resin. At concentrations of 5 wt. % DDGS with particles of 500 μm produced superior properties compared to the control panel were achieved while the other blends remained equivalent to the control.