Many factors related to disease etiology, animal behavior, and comparative physiology combine to complicate the testing of vertebrate pesticides for use in disease control. Several case histories and documented events are referred to as a means of delineating the diverse nature of these difficulties. Because of the great variety of experiences and formal education necessary to evaluate these problems effectively, it is obvious that a multidisciplinary, consensus effort is required. The exceedingly high cost and low return for investment and labor in research would indicate that no single agency, company, nor group of scientists are capable of, nor can afford, undertaking pesticidal registration for vertebrate disease control under the usual criteria. Therefore, special consideration for a multiagency, multidisciplinary approach to the development of pesticides for disease control in vertebrate animals is mandatory, if catastrophes to human and environmental health are to be minimized.