There is now a body of research that has shown that the attitudes of nurses towards substance misuse in the mentally ill are generally suboptimal and this has an impact on the quality of nursing care provided. Despite this, to date there have been no published studies that have examined the attitudes of forensic nurses towards substance misusing forensic service users. Sixty-three multiethnic registered forensic psychiatric nurses based on an inpatient unit in outer London were surveyed using the Substance Abuse Attitude Survey (SAAS). This has five subscores: Treatment Intervention, Treatment Optimism, Permissiveness, Non-Moralism and Non-Stereotypes. Only Permissiveness scores were at an optimum level and equivalent to other community mental health workers. The Treatment Intervention and Treatment Optimism subscores were well below those of a multidisciplinary group of community mental health workers. Three other findings were of note. Firstly, women had higher Non-Moralism scores than men. Secondly, staff nurses had higher Non-Stereotypes scores than other grades. Finally, Black nurses had higher Treatment Optimism scores than non-Black colleagues. In conclusion, the attitudes of forensic nurses towards substance misuse in forensic clients are more suboptimal than other groups of community mental health workers. Our findings also indicate that gender, staff grading and ethnicity are associated with suboptimal scores.