Female street sex workers in the UK are often addicted to heroin, and sex work may be a result of the economic drive to fund this addiction. This study looks at outcomes of a primary care drugs treatment intervention for street sex workers who use heroin, using prescribed maintenance treatment with intensive health and psychosocial support. Thirty-four sex workers entered the study and 100% were retained in the study at 1 year. After 1 year, only 33% of participants were still sex workers. Quality of life had improved significantly and heroin use had reduced.