A new carbapenem antibiotic, C-19393 E5, was isolated from the culture filtrate of Streptomyces griseus subsp. cryophilus C-19393 as a minor component. The chemical structure of the antibiotic was determined by comparing its spectral data with those of the known 5,6-cis carbapenem antibiotics and confirmed by partial synthesis from epithienamycin B as shown in Fig. 1. The antibiotic has a broad antimicrobial spectrum and shows strong inhibitory activity against beta-lactamases.