An important aspect of heat-shock response of lupin (Lupinus albus cv. Rio Maior) is the formation of cytoplasmic granular aggregates, called heat-shock granules (HSGs). In this study, two-dimensional electrophoresis (2-DE) was used to detect the component proteins of HSG complexes formed in vivo. Evaluation of 2-DE revealed differential expression of several proteins under heat shock conditions when compared with control. Among them, small heat-shock proteins (sHSPs) of 15 to 30 kDa were found to be the major representative proteins along with other proteins of relative molecular mass ranging from 36 to 45 kDa and above.