Antibiotic-resistant Corynebacterium strains were isolated from 14 Harborview and one Veterans Administration Hospital patients in Seattle during the period 1987-90. These clindamycin-erythromycin resistant strains were shown to hybridize with the ermCd gene, which was cloned from a Corynebacterium diphtheriae plasmid and encodes for a rRNA methylase. Thirteen of these strains also hybridized with the tetM gene probes, and were tetracycline resistant. The ermCd gene could be transferred, by conjugation, while the tetM gene was not transferable.