The working environment is an important determinant of employee well-being. Previous UK studies report registered nurses' perception of the working environment using the Work Environment Scale (WES), but surprisingly few include data for nurses working in mental health or learning disability settings. One hundred and sixty-one (58.8%) registered nurses working day shifts in five specialist divisions (forensic adult mental health, adolescent mental health, elderly continuing care, adult and adolescent learning disability and brain injury rehabilitation) of a large charitable hospital comprising mostly secure (i.e. 'locked') wards completed the WES. Nurses working in separate clinical divisions differed only on the 'physical comfort' subscale. These results are discussed in the context of previous UK research: this sample of nurses scored differently on a number of subscales, with the working environment characterized by relatively high levels of support, cohesion and managerial control and slightly lower levels of autonomy. It is unclear whether the differences reflect the organizational (i.e. non-NHS) context, or a secure environment effect. Previous studies of mental health nurses are now 10 years old and we present data that may provide a benchmark of perceptions of the working environment held by nurses working in mental health and learning disability settings.