The feasibility of providing postdetoxification residential substance abuse programming (stabilization) in large emergency shelters was examined as part of a demonstration project funded by the National Institute on Alcohol Abuse and Alcoholism under Section 613 of the Stewart B. McKinney Act (Public Law 100-71). The program completion rates of 773 homeless/near-homeless substance-abusing individuals assigned to two large shelters (71% and 62%) and two traditional substance abuse treatment agencies (68% and 54%) were comparable. These data support the expansion of shelter services to include substance abuse programming and intervention. Shelters represent windows of opportunity into the lives of homeless substance-abusing men and women, and full advantage of this opportunity should be taken to impact this subgroup of the homeless.