A community health worker (CHW) is a member of a community who provides basic health and medical care within their community, and is capable of providing preventive, promotional and rehabilitation care to that community, typically without formal education equal to that of a nurse, CHO, or doctor. They are chosen within the community to assist a train personnel community health extension worker who is train in college or schools of health. A community health extension worker (CHEW) is a specially trained professional who provides similar preventive, curative and rehabilitative health care and services to people where they live and work. CHEW are trained for three years and they graduate with a diploma, while the JCHEW are trained for two years and graduate with a certificate. Other terms for this type of health care provider include lay health worker, village health worker, community health aide, community health promoter, and health advisor.

Community health officers contribute to community development and can help communities improve access to basic health services. They are most effective when they are properly trained to provide information and services to the community. Community health officers are the most promising form of delivering health services to resource-constrained areas. They are seen as secondary health services in most low-income countries are available as a service to the community.

In many developing countries, especially in Sub-Saharan Africa, there are critical shortages of doctors. Current medical schools cannot train enough workers to keep up with increasing demand for health care services, internal and external emigration of health workers, deaths from AIDS and other diseases, low workforce productivity, and population growth. Community health officer are trained after completing their basic community health extension worker training in the colleges of health technologies, this training takes place in teaching hospitals that offers community health officer training to equip them with the knowledge to carry out more advanced health service in the rural areas. The community health officers work in primary health centre where they spent 70% of their time attending to patients and 30% in the community. community health officers can trained volunteer village health workers and community health workers chosen by the community that he or she works to help communicate with the local people. Programs involving community health officers in China, Brazil, Iran and Bangladesh have demonstrated that utilizing such officers can help improve health outcomes for large populations in under-served regions.^{[citation needed]} "Task shifting" of primary care functions from professional health workers to volunteer village health is considered to be a means to make more efficient use of the human resources currently available and improving the health of millions at reasonable cost.

Community health officers (CHO), also called mid-level health providers (MLHP) and non-physician practitioners, are trained health care providers who have a defined scope of practice. In India, only nurses and AYUSH practitioners are eligible for this cadre. This means that they are trained and legally permitted to provide healthcare in fewer situations than physicians but more than other health professionals.

Recently in India, community health officers at Ayushman Bharat Health and Wellness Centres are now allowed to supply certain medicines to the patients, as they have been included in Section 23 of Schedule K of Drugs and Cosmetics Rules, 1945. In India, community health officer (CHO) is another name for mid-level practitioner.

Ministry of Health and family welfare, Government of India published guidelines for prevention and controlling of COVID-19 cases in rural area of India. According to guidelines, symptomatic cases can be triaged at the village level by tele-consultation with a community health officer (CHO), and cases with comorbidity or low oxygen saturation should be sent to higher centres.

It is unclear where the usage of community health workers began, although China and Bangladesh have been cited as possible origins. Melinda Gates, co-founder of the Bill & Melinda Gates Foundation, said the nongovernmental organization BRAC in Bangladesh "pioneered the community health worker model." Catherine Lovell writes that BRAC's decision to train locally recruited paramedics was "based on the Chinese barefoot doctor model then becoming known worldwide."

Scientific medicine has evolved slowly over the last few millennia and very rapidly over the last 150 years or so. As the evidence mounted of its effectiveness, belief and trust in the traditional ways waned. The rise of university-based medical schools, the increased numbers of trained physicians, the professional organizations they created, and the income and attendant political power they generated resulted in license regulations. Such regulations were effective in improving the quality of medical care but also resulted in a reduced supply of clinical care providers. This further increased the fees doctors could charge and encouraged them to concentrate in larger towns and cities where the population was denser, hospitals were more available, and professional and social relationships more convenient.