The success of the Program for Assertive Community Treatment (PACT) has led to its replication with different client populations, especially those who are underserved by the traditional treatment system. This paper describes a program in Baltimore that has adapted the PACT model to serve homeless persons with severe mental illness. Although the essential ingredients and philosophy of the original model were maintained, the original team approach has been modified by the use of "miniteams." All staff share knowledge of all program clients through formal mechanisms such as daily meetings; however, each client is assigned to a miniteam composed of a clinical case manager, a psychiatrist, and a consumer advocate. Another deviation from the PACT model is that services can be time limited. The authors describe four phases of treatment and problems, including interventions characteristic of each phase.