Antibodies against alpha smooth muscle actin (ASMA) and S100 protein were applied to paraffin wax embedded sections from 40 salivary gland tumours and seven normal salivary glands. The results indicate that ASMA is useful in the diagnosis of epithelial-myoepithelial carcinoma, but is otherwise only of limited use in diagnostic practice. An unexpected finding was the failure of ASMA to react with myoepitheliomas.