OASW has over 3,400 members in 15 branches across the province. It is a bilingual membership organization and was incorporated in 1964. OASW belongs to the Canadian Association of Social Workers (CASW) which, in turn, is part of the 78-nation International Federation of Social Workers (IFSW). Members represent all areas of practice ranging from direct services to clients to community and organizational development, policy work, education and research. To be eligible for membership in OASW, one must be a graduate from or a student in an accredited university-based program in social work at the bachelor's (BSW), master's (MSW) or doctoral (Ph.D/DSW) level.

OASW's purpose is to address the interests and concerns of social workers. Bound by the profession's code of ethics, a major role is to comment on public policies that affect clients whom social workers serve. Human rights and the needs of under-served or at-risk populations are priorities. In addition, OASW focuses attention on increasing public awareness on the important role played by the profession related to service delivery. Furthermore, we speak on behalf of the profession regarding a wide array of professional practice and employment issues such as government or organizational policies that potentially infringe on our scope of practice.