The objectives of this work were to study the toxic emissions of metals, dioxins and furans, released during co-combustion of waste wood - coal in an industrial boiler and to determine the relation of the toxic emissions to the fuel properties. Co-combustion experiments were performed in an industrial moving grate combustor. The fuels used in the co-combustion tests included high ash Greek lignite, natural uncontaminated wood, power poles and Medium Density Fibers, a by-product from the industrial process line. Fuel blends were prepared by mixing single waste wood components with lignite in various concentrations. Gaseous and particulate samples collected during the experimental runs were analyzed for heavy metals, dioxins and furans according to standard methods. Low emissions of toxic pollutants were obtained during the co-combustion tests, lower than legislative limit values. The lowest values of dioxins and furans were observed during combustion of fuel blends containing MDF, possibly due to inhibitory action of some of the N-containing MDF ingredients. No direct correlation was found between PCDD/F and metal; especially copper-emissions.