A six to seven year-old female okapi died after a week of illness showing clinical signs of an acute infection of the respiratory tracts. Antibiotic therapy did not influence the course of the disease. The postmortem examination demonstrated the presence of acute laryngitis, tonsilitis, tracheo-bronchitis, bronchopneumonia and serifibrinous exudate, together with a subacute and subchronic myocarditis and hepatitis. Bacteriological cultures from the spleen, liver, kidneys, and the lungs, yielded two strains of Escherichia coli. Forty-eight hours after the death of the female, the male okapi became ill and it was treated with antibiotics indicated by the sensitivity tests carried out upon the Escherichia coli noted in the dead female: ampicilline was thus injected into the male whose health gradually improved and a complete recovery occurred.