Asom Gana Parishad (AGP) was the outcome of the six-year-long Assam Movement, which was spearheaded by the All Assam Students Union (AASU) and the All Assam Gana Sangram Parishad (AAGSP) asking the central government to free Assam of several million illegal infiltrators from across the borders. For many years, the people of Assam were raising the demand for steps against the illegal foreign infiltrators who had entered the state of Assam through the porous border, mostly from Bangladesh (erstwhile East Pakistan) and occupied vast areas of the state, thus threatening the economic, political, social and cultural existence of the indigenous people of the state.

When the revision of the electoral rolls of Mangaldoi Loksabha Constituency was undertaken following the death of sitting MP, Hiralal Patwari, in 1978, the real situation came to light. During the process of the election, observers noticed that the number of registered voters had grown dramatically. Immediately, the AASU under the leadership of Sri Prafulla Kumar Mahanta (President) and late Bhrigu Kumar Phukan (General Secretary) demanded action against the infiltrators. The people of Assam joined AASU in demanding the postponement of the bye-elections to Mangaldoi Loksabha Constituency and a thorough revision of all the electoral rolls of the state in order to detect (foreign infiltrators), delete (from Voters’ lists) and deport all the illegal infiltrators. This rapidly turned into a Mass Movement throughout the state and the Assam Movement was born in 1979. Many organizations like the Asom Sahitya Sabha, the Sadau Asom Karmachari Parishad, Asom Jatiyatabadi Yuva-Chatra Parishad, Asom Yuvak Samaj, All Assam Central and semi-Central Employee’s Association etc. including two regional political parties- Purbanchaliya Lok Parishad(PLP) & the Asom Jatiyabadi Dal(AJD) joined hands with AASU and constituted the All Assam Gana Sangram Parishad (AAGSP) to guide the Movement. The Movement continued for six long years and during these years, more than 800 martyrs sacrificed their lives for the cause of the state. Countless others suffered serious injuries including bullet injuries, many became permanently handicapped.

The central government had to come to the negotiation table and discuss a solution with the movement leaders, AASU and AAGSP. Several rounds of discussions with successive governments in New Delhi culminated in the signing of the Assam Accord on August 15, 1985 between AASU, the AAGSP and the Central Government in presence of the then Prime Minister, Late Rajiv Gandhi. The Assam movement has come to be regarded as one of the longest peaceful movements in the world after the freedom movement of India.

Following the Assam Accord, the State Assembly was dissolved and the Congress Government of Late Hiteswar Saikia, which came to power in February 1983 in an election completely boycotted by the people of Assam, was dismissed paving the way for democratic elections.

The AASU called for a Convention of the people of Assam at Golaghat from 13th to 14th October, 1985, where it was decided to constitute a regional political party under the name of Asom Gana Parishad (AGP) and the party was formally launched at Golaghat on October 14, 1985. Prior to that the then Central Executive Committee of the All Assam Students’ Union with Sri Prafulla Kumar Mahanta as President and Bhrigu Kumar Phukan as General Secretary handed over the leadership of the student organization to a new batch of leaders at a convention held in Lakhimpur in September, 1985.

When the AGP was formed, the first presidium was headed by Sri Prafulla Kumar Mahanta and Sri Bhrigu Kumar Phukan became one of the General Secretaries. The Six year peaceful democratic movement against the foreign infiltrators in Assam thus converted itself into a regional political organization with the then leadership of the AASU as the flag-bearers and the two existing regional parties, PLP and AJD merged into it along with several other organizations. The AGP decided to contest the elections to the state assembly held in December 1985 and swept the polls by winning 67 of the 126 seats apart from capturing seven of the 14 Lok Sabha constituencies and formed a new Government in Assam. Sri Prafulla Kumar Mahanta became the youngest Chief Minister in India at the age of 33, heading the first Asom Gana Parishad (AGP) government in Assam.