Blending of polyethylene with lignin in concentrations > 20 wt % yielded blends with relatively low mechanical properties. A new method, based on modification of polyethylene with ethylene-vinylacetate (EVA) copolymer, eras developed for the preparation of polyethylene blends containing about 30 wt % lignin with acceptable strength properties. The addition of 10 wt % EVA caused an increase of tensile strength about twice and elongation at break about 13 times compared to those of the corresponding nonmodified samples. The optimization of lignin-poly-ethylene-EVA blend composition was based on a regression equation, which was obtained as output from an experimental design. The prepared composite material with 33.6 wt lignin showed acceptable processing and mechanical properties. (C) 2004 Wiley Periodicals, Inc.