Polyclonal specific antisera to beta-receptors were prepared by immunization of rabbits with beta-receptors isolated from a dog myocardium according to Becker et al. (1988). Cryostat sections of the dog heart were fixed in paraformaldehyde in PBS, and incubated with polyclonal antisera to beta-receptors. Sections were then washed and incubated in peroxidase-labelled anti-rabbit antibody. After visualization of the tissue-bound peroxidase with diaminobenzidine, sections were dehydrated in graded alcohols and mounted in Canada balsam. The results demonstrate specific reaction of antibodies on the myocyte sarcolemma.