Homeless shelters provide a unique opportunity to intervene with occupants who have substance abuse problems, as not addressing these issues may lead to continuation of problems playing a contributing role in homelessness. Attempts to implement Contingency Management (CM) with this population have often been complex, costly, and not straightforward to replicate in community settings. We conducted a randomized trial evaluating a simple, low-cost 4-week CM program for 30 individuals seeking shelter in a community-based homeless shelter who had both current substance and psychiatric disorders. Behavioral assessments were performed at baseline, weekly, and termination of the study. Overall retention in the trial was high; participants assigned to CM reduced their cocaine and alcohol use more than those in assessment-only. This pilot trial suggests that application of low-cost CM procedures is feasible within this novel setting and may decrease substance use.