Several taxonomically unrelated true fungi produce penicillins, and one species of Streptomyces has been reported to yield penicillin N. Cephalosporin C (1) has been isolated from only one species of Cephalosporium. We report here the identification of penicillin N, and isolation and structure elucidation of three new β-lactam antibiotics of the cephalosporin C type from two species of Streptomyces. Metabolite 2 was produced by a strain of Streptomyces lipmanii NRRL 3584. A new streptomycete species, Streptomyces clarjuligerus NRRL 3585, afforded antibiotics 3 and 4.