Jagdeo, a 42-year-old ethnic Indian, won 64.6 per cent of the vote while his People's Progressive Party/Civic party won 36 seats in the 65-member parliament, Gocool Boodoo, Guyana's chief election officer, said on Thursday.
"This is an endorsement of our track record," Jagdeo said looking relaxed as supporters cheered at his campaign headquarters. "Now the election is over, we need to put aside the campaign rhetoric."
Guyana, an impoverished nation wedged between Venezuela and Suriname, seemed to escape the violence of past votes. Tensions between the Indian majority and Afro-Guyanese boiled over into rioting after elections in 1992, 1997 and 2001.
Jagdeo, educated as an economist in Russia, won support for building more roads, water pipelines and schools. But Guyana, with just 750,000 people living in an area the size of Britain, still struggles with poverty, crime and scarce investment.
Robert Corbin, a key opponent who charges Jagdeo with ignoring Afro-Guyanese issues and turning a blind eye to corruption, had denounced irregularities and accused the PPP/C of fraud at some polling stations.
Observers from the European Union and the Organisation of American States noted some difficulties in the voting, but generally applauded the election as a success after past violence in South America's only English-speaking country.
Rich in bauxite, gold and timber, Guyana gained its independence from Britain in 1966. Most residents are either descendants of African slaves or of indentured workers brought from India and China to work on sugar plantations.