We tested the specificity of three commercially available antibodies (AB) against individual α1-adrenergic receptor subtypes (α1-ARST). We used these ABs to localize the α1-ARST proteins by immunohistochemistry in paraffin-embedded murine tissues. The specificity of the ABs was tested by comparing staining patterns in tissues from wild-type mice with those in corresponding tissues from mice with gene-targeted disruption of the respective α1-ARST, one of the most rigorous negative controls. None of the tested ABs proved to be specific for the indicated target antigen. We conclude that the tested ABs are unsuitable for immunohistochemistry in paraffin-embedded murine tissues.