Microbiological, kinetic and clinical studies were conducted on a new cephamycin, cephotetan. In vitro the antibiotic was found to be very effective against all strains tested. It had a particularly strong action against Gram negative bacteria too. Kinetically speaking, an intravenous bolus produced a high plasmatic concentration with a half life of about 4 hours. Elimination via the kidneys was fastest in the first 3 hours after administration (49.82%) and the slowed down. 82.76% of the dose administered was excreted within 24 hours. This antibiotics is particularly indicated in cases of urinary, respiratory and biliary infections.