This study examines the prevalence and characteristics of homelessness episodes in Australian substance misuse treatment. A dataset containing all closed substance treatment episodes in NSW, Australia from July 2006 to June 2011 was used. Statistical analysis was used to determine any relationships between demographic and treatment variables and homelessness. Of the 213, 129 treatment episodes in the dataset 12.8% have some form of homelessness. Non-government and residential services have the highest prevalence of homelessness. Sex, age, and drug type have weak relationships with homelessness. Leaving against the advice of the treatment provider is more common in episodes where homelessness is a factor. Homelessness is a problem experienced by a significant proportion of the substance treatment population and treatment providers have an opportunity and an obligation to address it in their treatment delivery.