increased collaboration between health professionals has been identified as a means of improving the quality of client care while operating within the constraints of a publicly funded health care system. one such model of collaboration is the interprofessional care (ipc) model. ipc features a high degree of collaboration between a team of providers from varying health professions that coordinate services for each client, conceptualized to result in holistic and clientcentred care. these features have intuitive appeal for treating the range of affected functioning in severe and comorbid disorder. as a result, the model has been increasingly used across medical and mental health care settings, perhaps best exemplified by its identification as the strategy for ontario health care renewal. however, this growth has occurred despite the lack of a necessary evidence base demonstrating the effectiveness of the model in actual practice. the current study assessed the statistical and clinical significance of ipc in a community outpatient mental health setting, treating 183 adults with severe and comorbid disorder. of interest was the change in clients’ reported symptoms and functioning over the course of treatment and at follow-up. clients demonstrated statistically and clinically significant change in symptoms (depression and anxiety, impulsive and addictive behaviours, and psychosis) and functioning (relation to self and others, daily living) at discharge associated with ipc, while analysis of follow-up assessment identified areas for future research. results provide foundational evidence supporting the use of ipc in mental health care. implications for clinicians and directions for future research are provided.