Role of the professional social worker
Professional social workers have a strong tradition of working for social justice, and of refusing to recreate unequal social structures.  This means going beyond state sponsored practices which merely cater for individual needs, in order to transform society as a whole.  Social work maintains this radical kernel and today many social workers internationally have strong connections with social and political movements for the emancipation of the oppressed.
The main tasks of professional social workers are case management (linking clients with agencies and programs that will meet their psychosocial needs), medical social work, counseling (psychotherapy), human services management, social welfare policy analysis, community organizing, advocacy, teaching (in schools of social work), and social science research.
Professional social workers work in a variety of settings, including: non-profit or public social service agencies, grassroots advocacy organizations, hospitals, hospices, community health agencies, schools, faith-based organizations, and even the military. Other social workers work as psychotherapists, counselors, or mental health practitioners, normally working in coordination with psychiatrists, psychologists, or other medical professionals. Additionally, some social workers have chosen to focus their efforts on social policy or academic research into the practice or ethics of social work. The emphasis has varied among these task areas by historical era and country, and some of these areas have been the subject of controversy as to whether they are properly part of social work's mission.

# Role of social work in the USA
In the United States of America, leaders and scholars in the field of social work have debated the purpose and nature of the profession since its beginning in the late 1800s.  Workers, beginning with the settlement house movement, have argued for a focus on social reform, political activism, and systemic causes of poverty. Social workers of the Settlement House Movement were primarily young women from middle-income families and chose to live in lower-income neighbourhoods to engage in community organizing. These workers sometimes received stipends from charitable organizations and sometimes worked for free.
In contrast to the settlement house movement, the friendly visitors were women from middle-income families who visited (but did not reside among) families in lower-income neighbourhoods. Friendly visitors emphasized conventional morality (such as thrift and abstinence from alcohol) rather than social activism.
Others have advocated an emphasis on direct practice, aid to individual clients and families with targeted material assistance or interventions using the diagnostic and statistical manual of mental diseases DSM-IV. While social work has been defined as direct, individual practice in last quarter of the twentieth century, there is a growing resurgence of community practice in social work.  Of broad and growing significance are the relationship counseling and Relationship Education movements which seek to assist in interpersonal social skill building which can be of great societal value in promoting marriage and family stability.  Relationship education and counseling primarily aid that majority of individuals who are free of pathology or who have found that DSM-IV based services are ineffectual.  This majority can benefit from education and exposure to relationship skills that have not otherwise been discussed and distributed by social services in this time of weakened family, church, and societal conventions. Another new development in social work is the focus on informatics (Parker-Oliver & Demiris, 2006).  For many social workers, the use of any online technology is problematic due to persistent concerns about privacy. However, other social workers recognize that clients are going on line for many purposes.  Some schools of social work, such as University of Southern California are offering courses to build informatics skills at the graduate level.
Community practice is the new term of art for what used to be known as "macro practice" social work. Community practice includes working for change at the systems level, including human services management (administration, planning, marketing, and program development); community organizing (community development, Grassroots Organizing, policy advocacy); social policy and politics; and international social development.
The National Association of Social Workers (NASW) is the largest and most recognized membership organization of professional social workers in the world.  Representing 150,000 members from 56 chapters in the United States and abroad, the association promotes, develops and protects the practice of social work and social workers.  NASW also seeks to enhance the well-being of individuals, families, and communities through its work and advocacy.
Although membership is generally not required for licensure, NASW survey data give a rough idea of how social workers are employed in the US. According to NASW:
Nearly 40% of NASW members say that mental health is their primary practice area. The health sector employs 8% of NASWs members, and 8% practice in child welfare or family organizations. Six percent of NASW members say school social work is their primary practice area, and another 3% work primarily with adolescents. (NASW, 2005) These figures are significantly confounded by the fact that NASW members are primarily licensed practitioners working in the clinical arena, and the fact that many social workers in the field do not actually hold a degree in social work. NASW is usually concerned with issues like licensing, reimbursement, etc., that are not relevant to child welfare practice, for instance.
Within the mental health field, social workers may work in private practice, much like clinical psychologists or members of other counselling professions often do.  Social workers are often in the position of recommending the use of psychopharmaceutical agents, though not prescribing them.  The increasingly widespread usage of these agents in the U.S. has received little scrutiny by the NASW, despite that fact that these drugs are prescribed far more heavily in the U.S. than anywhere else in the world.  Social workers in private practice may take direct payments from clients and may also receive third-party reimbursement from insurance companies or government programs such as Medicaid.  Insurance reimbursement for mental health services involves the designation of the recipient of services as mentally ill, or more specifically a label is assigned from the DSM-IV, the diagnostic and statistical manual of mental illness.  This assignment, when recorded to an individual's medical history can prove to be a significant impediment to future pursuits.  It can raise the cost to the individual for health or nursing home insurance; it can be the basis of denial for life insurance; and it can limit an individual's professional choices, such as in health care, motor vehicle operation, or airplane piloting.
Private practice was not part of the social work profession when it began in the late 1800s, and private practice has been controversial among social workers, some of whom feel that the more lucrative opportunities of private practice have led many social workers to abandon the field's historic mission of assisting disadvantaged populations. The private practice model can be at odds with the community development and political activism strains of social work.
Social workers in mental health may also work for an agency, whether publicly funded, supported by private charity, or some combination of the two. These agencies provide a range of mental health services to disadvantaged populations in the US.
Some social workers are child welfare workers, a role that looms large in the public's perception of social work.  This role contributes to a negative view of social work in the U.S., since child welfare authorities can remove abused or neglected children from the custody of their parents, a practice that is fraught with controversy and sometimes with scandalous incompetence.  Many child welfare workers in the US do not in fact have social work degrees (though all caseworkers in most states have at least a Bachelor's degree in a related field).
Some states restrict the use of the title social worker to licensed practitioners, who must hold a degree in the field. Such restrictions are a high legislative priority of NASW.

# Role of social work in the United Kingdom
In the United Kingdom and elsewhere, a social worker is a trained professional with a recognised social work qualification, employed most commonly in the public sector by local authorities.
Spending on social services departments is a major component of British local government expenditure.
In the UK, the title "social worker" is protected by law (since 1 April 2005) and can be used only by people who have a recognised qualification and are registered with the General Social Care Council (in England), the Scottish Social Services Council, the Care Council for Wales (Welsh: Cyngor Gofal Cymru), or the Northern Ireland Social Care Council.
The strategic direction of statutory social work in Britain is broadly divided into children's and adults' services. Social work activity within England and Wales for children and young people is under the remit of the Department for Children, Schools and Families while the same for adults remains the responsibility for the Department of Health. Within local authorities, this division is usually reflected in the organisation of social services departments. The structure of service delivery in Scotland is different.
Within children services some social workers are child protection workers, a role that looms large in the public's perception of social work.  This role contributes to a negative view of social work in the U.K., since child protection workers for local authorities can remove suspected abused or neglected children from the custody of their parents, a practice that is fraught with controversy and media criticism.
In 2007, the General Social Care Council launched a wide-ranging consultation, in concert with a number of other social care organisations, to agree a clear professional understanding of social work in the UK