Previous research has demonstrated that characteristics of the health care workplace influence staff outcomes such as morale and burnout, but the potential effect of health care workplaces on the treatment environment has been little studied. Building on a model proposed by Schaefer and Moos (1993), we propose that the workplace factors of supervisory work environment (e.g. support from supervisors, managerial control) and programme philosophical orientation (e.g. disease model of addiction, psychosocial learning model of addiction) predict four treatment environment elements: patient autonomy, staff control, staff sensitivity, and patient alienation. Multiple regression analysis of data drawn from a survey (response rate=86%) of 327 staff members at 15 Veterans Affairs (VA) inpatient substance abuse treatment programmes revealed that greater managerial control over staff predicted greater patient alienation, lower staff sensitivity towards patients, and greater staff control over patients. Stronger disease model programme orientations predicted less patient alienation and greater staff sensitivity, whereas stronger psychosocial model programme orientations predicted less staff control. These results suggest that health care workplaces may influence treatment environments. Implications for further research and practice are discussed.