Fibers from renewable resources are gaining interest for use as fillers in hybrid composite materials. Particularly waste material such as sugar cane bagasse offer large availability, biodegradability, and low cost. Influence of single components on composite material properties is an important parameter to be evaluated. Composites of poly(vinyl alcohol) (PVA) at 88 and 98% saponification degrees and sugar cane bagasse (B) were prepared by casting water suspensions of the components and characterized for their dynamic mechanical behavior. The storage modulus below and above the glass transition and the shape of the relaxation process are strongly influenced by the amount of B. Good adhesion was observed at the lignocellulosic fibersynthetic polymer interface. Urea and glycerol are able to plastify the PVA/B composites thus giving rise to a decrease of the glass transition temperature and to a widening of the glass transition temperature gap. (C) 2004 Wiley Periodicals, Inc. J Appl Polyrn Sci 92: 426-432, 2004.