beta-Lipoprotein was isolated by the precipitation method from collective serum of 47 men aged 27-49 years (mean 42-1 years) exposed to carbon disulfide during work over long periods of time. Significantly elevated levels of serum beta-lipoprotein, clinical and polycardiographic symptoms were found in 85-1% of subjects. Antibodies to beta-lipoprotein obtained by immunizing rabbits intravenously were compared with similar antibodies in healthy subjects by double immunodiffusion in agar and by the passive hemagglutination test. Both tests showed identical antigens.