A lectin present in seeds of Trigonella foenumgraecum was isolated and purified by acid precipitation, salt fractionation, and affinity chromatography on mannan cross-linked agarose. SDS-PAGE revealed a single band corresponding to a molecular weight of 27,350 daltons. The lectin agglutinated trypsin-treated rat erythrocytes. Sugar specificity as determined by hemagglutination inhibition assay indicated that the lectin belongs to a glucose/mannose-specific group. The reaction of the lectin with glycoprotein was affected by pH changes. The carbohydrate binding specificity of the lectin was investigated by turbidity and activity measurements. As the lectin belongs to the Leguminoceae family, the specificity of the lectin for glucose/mannose renders it a valuable tool for Rhizobium-legume symbiosis.