Infections and diseases are a major cause for concern as well as loss of animal life in the zoo setting. This problem is the result of contact with agents such as bacteria, fungi, parasites, rickettsia, chlamydia, or viruses. Control of such infections and diseases is difficult principally because of the design and purpose of the zoo itself. However, infection and disease can be minimized with appropriate recognition of the problem and training of personnel to limit the spread of infectious organisms. Biohazards need to be considered not only among the various animal populations, but with regard to human contacts, particularly in relation to nonhuman primates.