Title/Aim: Developing a comprehensive, integrated and contemporary recovery oriented dual diagnosis service, within the environment of primary and continuing care in Cork, Ireland. Background: The mental health services and addiction services, generally function independently of one another. Where an individual experienced mental ill health and addiction simultaneously, access to appropriate services was compromised. In this, no specific service was locally available. Objectives:  To engage stakeholders in PAR’s methodological framework to facilitate a clear pathway to services  To engage stakeholders in a critical reflective process of inquiry  To enact pragmatic developments in service delivery that demonstrates positive outcomes for clients  To contribute to learning, knowledge development and new ways of knowing Methodology: Participatory Action Research (PAR) methodologies were adapted to a Health Service Executive (HSE) organisational context, where three research cycles (phases) of inquiry enabled the development of a new dual diagnosis (mental health and addiction) service. Methods employed included, field notes, journaling, individual interviews, participant observation and case studies. Pragmatism was employed as the most suitable guiding theoretical perspective that underpinned the inquiry process. Findings: Cycle One demonstrated that emerging percepts shaped the formation of required service developments, leading to the emergence of a practical theory. Cycle Two included the implementation of service developments initiated in Cycle One. Findings demonstrated participant perspectives of the evolving service, while stakeholders developed the service’s operational policy. The service developments were embedded further, contributing to service sustainability. New percepts emerging, contributed collectively to further refinement of the practical theory. Cycle Three included practice transformation, where representatives from relevant organisational-hierarchical tiers participated in the implementation of the new dual diagnosis service. Some percepts ended upon implementation, while others modified the practical theory further. Findings from participants’ case studies demonstrated application of the theory in practice. Contribution to knowledge and service development: In this study, PAR has demonstrated efficacy as a transforming agent through new ways of doing – evident in the design, construction and implementation of a dual diagnosis service. Within this inter-relational process, a co-constructed perceptual framework and a new way of knowing has emerged. The three Cycles of this inquiry have exhibited how (a) the social validity criteria of comprehensibility, truth, rightness and authenticity were present, and (b) how the research claims made were validated, and can therefore be upheld.