We report findings from a community-based two-city survey of homeless adults comparing the level of substance abuse treatment assigned to them using the ASAM Patient Placement Criteria with care actually received during the previous 12 months. Overall 531 adults were surveyed with 382 meeting DSM-IIIR criteria of being in need of treatment or having a demand for treatment. Of those with a treatment need, 1.5% met criteria for outpatient care, 40.3% intensive outpatient/partial hospitalization care, 29.8% medically monitored care and 28.8% managed care levels. In contrast, of those receiving treatment (50.5%, 162 persons), almost all care received by this cohort was either inpatient or residential based (83.6%). Unsheltered homeless persons and those without insurance were significantly more likely to report not receiving needed treatment. Lack of treatment availability or capacity, expense, and changing one's mind while on a wait list were the most commonly cited reasons for no treatment.