Rotary is a worldwide organization of business and professional leaders that provides humanitarian  service, encourages high ethical standards in all vocations, and helps build goodwill and peace in the world. Approximately 1.2 million Rotarians belong to more than 32,000 clubs in more than 200 countries and geographical areas. 

Rotary club membership represents a cross-section of the community's business and professional men and women. The world's Rotary clubs meet weekly and are nonpolitical, nonreligious, and open to all cultures, races, and creeds.

The main objective of Rotary is service — in the community, in the workplace, and throughout the world. Rotarians develop community service projects that address many of today's most critical issues, such as children at risk, poverty and hunger, the environment, illiteracy, and violence. They also support programs for youth, educational opportunities and international exchanges for students, teachers, and other professionals, and vocational and career development.

The Rotary motto is Service Above Self.

Although Rotary clubs develop autonomous service programs, all Rotarians worldwide are united in a campaign for the global eradication of polio. In the 1980s, Rotarians raised US$240 million to immunize the children of the world; by 2005, Rotary's centenary year and the target date for the certification of a polio-free world, the PolioPlus program will have contributed US$500 million to this cause. In addition, Rotary has provided an army of volunteers to promote and assist at national immunization days in polio-endemic countries around the world.

The Rotary Foundation of Rotary International is a not-for-profit corporation that promotes world understanding through international humanitarian service programs and educational and cultural exchanges. It is supported solely by voluntary contributions from Rotarians and others who share its vision of a better world. 
Since 1947, the Foundation has awarded more than US$1.1 billion in humanitarian and educational grants, which are initiated and administered by local Rotary clubs and districts. 

Rotary's popularity spread throughout the United States in the decade that followed; clubs were chartered from San Francisco to New York. By 1921, Rotary clubs had been formed on six continents, and the organization adopted the name Rotary International a year later.

As Rotary grew, its mission expanded beyond serving the professional and social interests of club members. Rotarians began pooling their resources and contributing their talents to help serve communities in need. The organization's dedication to this ideal is best expressed in its principal motto Service Above Self. Rotary also later embraced a code of ethics, called The 4-Way Test, that has been translated into hundreds of languages. 

During and after World War II, Rotarians became increasingly involved in promoting international understanding. In 1945, 49 Rotary members served in 29 delegations to the United Nations Charter Conference. Rotary still actively participates in UN conferences by sending observers to major 
meetings and promoting the United Nations in Rotary publications. Rotary International's relationship with the United Nations Educational, Scientific, and Cultural Organization (UNESCO) dates back to a 1943 London Rotary conference that promoted international cultural and educational exchanges. Attended by ministers of education and observers from around the world, and chaired by a past president of RI, the conference was an impetus to the establishment of UNESCO in 1946.

An endowment fund, set up by Rotarians in 1917 "for doing good in the world" became a not-for-profit corporation known as The Rotary Foundation in 1928. Upon the death of Paul Harris in 1947, an outpouring of Rotarian donations made in his honour, totaling US$2 million, launched the Foundation's first program — graduate fellowships, now called Ambassadorial Scholarships.
Today, contributions to The Rotary Foundation total more than US$80 million annually and support a wide range of humanitarian grants and educational programs that enable Rotarians to bring hope and promote international understanding throughout the world.

In 1985, Rotary made a historic commitment to immunize all of the world's children against polio. Working in partnership with nongovernmental organizations and national governments thorough its PolioPlus program, Rotary is the largest private-sector contributor to the global polio eradication campaign. Rotarians have mobilized hundreds of thousands of PolioPlus volunteers and have immunized more than one billion children worldwide. Rotary has contributed more than US$600 million to the polio eradication activities in 122 countries.   

As it approached the dawn of the 21st century, Rotary worked to meet the changing needs of society, expanding its service effort to address such pressing issues as environmental degradation, illiteracy, world hunger, and children at risk. The organization admitted women for the first time (worldwide) in 1989 and claims more than 145,000 women in its ranks today.
Following the collapse of the Berlin Wall and the dissolution of the Soviet Union, Rotary clubs were formed or re-established throughout Central and Eastern Europe.

Today, 1.2 million Rotarians belong to some 32,000 Rotary clubs in more than 200 countries and geographical areas.