Many Sudanese were working abroad in the mid-1990s, chiefly in Sa'udi Arabia and other Persian Gulf countries but also in Libya. Although their remittances were significant for the Sudanese economy, the absence of these workers, many of them skilled, constituted a "brain drain" of serious proportions. Perhaps 200,000 were expelled from Persian Gulf countries in 1991 because Sudan supported Iraq in the Gulf war.
As a result of the Sudanese government fighting the Sudanese People's Liberation Army in the south, there were still 209,000 Sudanese refugees in Uganda, 110,000 in the DROC, 78,000 in Ethiopia, 28,000 in Kenya, and 27,000 in the Central African Republic in June 1997.
Since the 1970s, the Sudanese government has welcomed refugees as a result of war or famine. As a result of UNHCR repatriation programs, 25,000 Eritreans and 62,000 Ethiopians were sent home in 1994 and 1995. At the end of 1998, Sudan was hosting an estimated 392,000 refugees, mainly from Eritrea, Ethiopia, Chad, Uganda, DROC, and Somalia. Of these, 162,000 were accommodated in camps, and 232,000 resided in urban areas. In 2000, the net migration rate was -2.6 migrants per 1,000 population. The total number of migrants in that year was 780,000, including 415,000 refugees. Worker remittances amounted to $638 million, or 5.8% GDP.