In Colorado Springs, arrest for patronizing a prostitute reduced rearrests for the same offense by approximately 70 percent. In other jurisdictions of the United States, however, arrest did not apparently reduce a client's patronizing of prostitutes. Approximately 2-3 percent of male residents in large metropolitan areas in the United States patronized local street prostitutes over observation periods of 2 to 5 years. Compared to the general male population, prostitutes' clients were more likely to be young, Hispanic, somewhat more likely to be Black, had substantially less education, were less likely to be married, and weighed a few pounds less on average than men in the general population. Clients of prostitutes were likely to engage prostitutes close to the client's residence. Violent clients and nonviolent clients were similar in age and distance between their residences and victim encounter/arrest locations; however, violent clients were less likely than controls to be White, be underweight or severely obese, and drive cars (as opposed to other types of motorized vehicles). Violent clients were also more likely to have a criminal history of violent and property offenses as well as rape. Prostitution arrest data were obtained from approximately 30 local U.S. jurisdictions and all 50 States. Data on arrested clients were compared with data on men in the general population. Nine diverse homicide datasets were analyzed to examine the extent, trend, and perpetrators of prostitution-related homicide. 8 tables, 2 figures, 26 references