Anti-α-D-mannose antibodies have been isolated from the serum of rabbits immunized with the glycoconjugate of α-D-mannose and bovine serum albumin joined by aminophenyl bridges. the antibodies were purified by affinity chromatography with adsorption on a mannosyl-Sepharose 4B column and elution with α-D-mannose or methyl α-D-mannoside. Such antibodies should be especially useful for studying the detection and progression of diseases caused by viruses, pathogenic microorganisms or transformed cells and could be useful as curative agents.