Abstract: Diurnal variation of allantoia (ALL) and allantoic acid (ALA) concentration occurs in nodules, roots, stems petioles and leaves of winged bean (Psophocarpus tetragonolobus DC.).The relationship between ALL, ALA concentration in each organs of winged bean plant was investigated. The corre-lativity between ureides concentration and ALL, A LA concentration in each organs was observed.The correlation between ALL/ureide and ureides,ALL, ALA and ALL/ureide in each organs was also detected, ALA concentration in rootshas a negative correlation to the ureides, ALL and ALA concectra-tion in each organs.ALA concentration correlates negatively to the ALL/ureide in nodules. ALA concentration in roots correlates negatively to the A-LL/ureide in roots and nodules, too. Our data suggests that ALA may have a feedback inhibition to ALL synthesis.