Changes induced in protein preparations from pea, bean and faba bean by hydroxyl radicals were determined in this study. Size exclusion chromatography showed that the proteins of legumes investigated are subjected to different changes. In pea and faba been proteins the radicals caused the increment of high molecular weight fraction (330-400 kDa) of resulted from fragmentation and polymerisation of low molecular weight subunits and, on the contrary, the main fraction of bean proteins (7S) undergoes partial fragmentation.