Halfdan T. Mahler, (21 April 1923 – 14 December 2016), was a Danish medical doctor. He served three terms as director-general of the World Health Organization (WHO) from 1973 to 1988, and is widely known for his effort to combat tuberculosis and his role in shaping the landmark Alma Ata Declaration that defined the Health for All by the Year 2000 strategy. He died on December 15, 2016 at the age of 96.

Career before WHO

Mahler's first international activities were in tuberculosis and community work in under-developed countries. He directed a Red Cross antituberculosis campaign in Ecuador between 1950 and 1951.

Career in WHO

In 1951, he joined the World Health Organization (WHO) and spent almost ten years in India as Senior WHO Officer attached to the National Tuberculosis Programme. From 1962, he was Chief of the Tuberculosis Unit at the WHO Headquarters in Geneva until 1969, when he was appointed Director, Project Systems Analysis. In 1970, he was made Assistant Director-General of WHO while retaining the direction of Project Systems Analysis. In 1973, while occupying that position, Mahler was elected WHO's third Director-General. In the same year, the Executive Board of WHO issued the report "Organizational Study on Methods of Promoting the Development of Basic Health Services". Mahler established a close rapport with Henry Labouisse. The agreement produced in 1975 a joint WHO-UNICEF report, Alternative Approaches to Meeting Basic Health Needs in Developing Countries, which examined successful primary health care in various countries. This report also criticized the idea of vertical approach methods of focusing on specific diseases as well as adding Western approaches to developing countries. The result of this report led the World Health Organization to carefully re-construct their approaches to Primary Health Care which led to a world wide debate.

Mahler gave a powerful speech at the 1976 assembly about how social structures are crumbling and about launching his Health for all by 2000 goal. He was re-elected for two successive five-year terms in 1978 and 1983 respectively. Under Mahler, in 1979, the Thirty-second World Health Assembly launched the Global Strategy for Health for All by the Year 2000. Mahler's "Health for All by the Year 2000" was criticized for being too broad and idealistic, and with the changing political climate of the 1980s health care began to move towards more selective and cost efficient approaches. Mahler was left to champion a more holistic and inclusive approach to health care on his own and with his departure as the director general, the WHO lost its political profile. He is honorary alumni of Copenhagen University From the late 1960s, under Mahler's lead, the WHO projects related to the development of "basic health services" were increased, these projects were the institutional predecessors of the primary health care programs that would later appear.