Abstract. The effects on crime rates of the intrusion of large numbers of strangers into an area are investigated. The sensitivity of six different crime types (murder, rape, assault, robbery, burglary, and larceny) to density of strangers is estimated using a standard model of criminal behavior. The variables which reflect this density are measures of tourists, college students, shoppers from other areas, opportunities to consume alcohol, and the presence of interstate highway exits. The results suggest that an increase in the number of strangers into an area has a positive effect on the crimes of burglary, larceny, and robbery, but very little effect on assault, murder and rape. A significant finding is that “wet” counties have a higher incidence of each crime type than do “dry” counties. From a policy standpoint, officials who support economic growth in urban areas should keep in mind that an increase in the opportunity for illegal activity accompanies such growth and plan accordingly. Copyright © 1990, Wiley Blackwell. All rights reserved