Cockroaches are arthropod transmitters of disease, acting both as mechanical vectors and as reservoirs of pathogenic agents. It has been shown that cockroaches harbor and transmit, both in nature and under experimental conditions, about 40 species of bacteria, including at least 25 from the Enterobacteriaceae group that cause gastroenteritis in man. In addition, it has been established that these insects are intermediate hosts of pathogenic helminths, viruses, fungi, and protozoa. It is possible that cockroaches contribute to the transmission of Chagas' disease by feeding on triatomine vectors of that disease. There also are signs that substances produced by cockroaches are involved in certain allergic processes. The foregoing facts are sufficient to justify the immediate control and eradication of these insects whenever and wherever they constitute a threat to public health.