The study excluded jails with a rated capacity of more than 500; this excluded jails in the most urbanized areas of the Nation. Only 1 percent of all U.S. jails have rated capacities above 500; yet they house more than 25 percent of the Nation's jail population. As a consequence, the study sample consisted of 180 jails that would be classified by most standards as "medium- large" to "large" and urban. Suicide and death by natural causes occurred in approximately 20 percent of the jails in the sample during 1978-83. Jails with more than one such death were more uncommon (approximately 50 percent of the sample). The skewed distribution of the numbers of suicides and natural deaths prevented the examination of dependent variables that tapped variations in the absolute number of deaths. The study yielded no overwhelming evidence that deaths from suicides or natural causes are related to jail variables; however, there was some evidence to suggest that the volume of admissions and releases as well as inadequate staff provisions create greater opportunities for jail deaths. The authors recommend that jailer training be structured to create greater awareness of inmate needs during critical periods of incarceration and to provide more emphasis on suicide prevention. Further, policies should be developed specifically for short-term detainees. 3 tables and 3 notes