1979: The first major wave of Afghan refugees enters Pakistan following the Soviet invasion. At least one million Afghans are estimated to have reached Pakistan by 1979, with a total of 3.3 million having fled to Pakistan and Iran by 1980.
1980: UNHCR sets up its first office in Pakistan in the wake of the refugee influx.
1981-1990: According to official Pakistan government figures, the number of registered refugees reaches two million by 1981, and 3.2 million by 1990, in addition to an estimated 500,000 unregistered refugees. As the influx continues in response to conflict, 334 official camps are established in Khyber Pakhtunkhwa, Baluchistan and Punjab provinces.
1994: Seventy-four thousand refugees arrive in Pakistan following fighting between Hezb-e-Islami and Jamiat-e-Islami, two of the Mujahdeen groups engaged in a struggle for the control of Afghanistan after the 1989 Soviet pull-out.
1996: The capture of the eastern city of Jalalabad and the capital Kabul by the Taliban brings 50,000 refugees to Pakistan’s North West Frontier Province (renamed Khyber Pakhtoonkhwa in 2010).
1998-9: The northern Afghan city of Mazar-i-Sharif falls to the Taliban, leading thousands more to flee to Pakistan.
1999: The complete takeover of Afghanistan by the Taliban pushes 30,000 new refugees, mostly ethnic Hazaras who fear discrimination, into Pakistan. Many head to southwestern Balochistan Province.
2001: After 9/11 the US begins attacks on militant targets in Afghanistan, prompting a fresh wave of migration to Pakistan. Around five million Afghans have crossed into Pakistan since 1979.
2002-2007: After the fall of the Taliban, the UNHCR assists 2.7 million Afghans to repatriate to Afghanistan from Pakistan. According to the agency, the 1.5 million who voluntarily went home in 2002 marked the single largest refugee return in the world since 1972. An estimated 1.1 million others return home independently, without UNHCR assistance.
2007-2012: Voluntary returns to Afghanistan decrease dramatically as a result of increased conflict in Afghanistan and a realization that there are few livelihood opportunities.
Sources: UNHCR, Commissionarate Afghan Refugees, KP, Human Rights Commission of Pakistan: Afghan refugees in Pakistan: Push comes to shove, April 2009, Middle East Institute, Herald magazine, Dawn daily, The News International
For more, visit IRIN's in-depth: From pillar to post – the plight of Afghans abroad