The present study investigated occupational stress levels in forensic psychiatric nurses within a medium secure unit for mentally disordered offenders and examined the possible relationships between aspects of the ward environment and identified stress levels. Data were obtained through self-report measures and unit statistics using a sample of 38 nurses on two secure (high and medium) wards. No significant differences in levels of occupational stress or perception of ward environment were observed between nurses on the two wards. Global ward atmosphere scores were compared with those of a maximum secure facility in the USA, showing the unit to be highly therapeutic. Occupational stress scores for all nurses were compared with normative regional data and showed elevated scores on broad view of control, satisfaction and type A behaviour. No demographic or ward environment variables were found to be associated with these high scores. Interpretations and implications are discussed.