Mr Ndayizeye has vowed to work for peace and economic recovery
Since taking over as president under a power sharing agreement, Domitien Ndayizeye has faced the challenge of maintaining good relations with Burundi's Tutsi-led army, while persuading Hutu rebels to stop fighting.
Mr Ndayizeye, a Hutu, succeeded Pierre Buyoya, a Tutsi, as head of a three-year transitional government on 30 April 2003. He had served as vice-president during Mr Buyoya's 18-month term.
The government was set up in November 2001 as part of efforts to end 10 years of civil war between the Tutsi minority, which has traditionally ruled the country, and the Hutu majority.
In November 2003 President Ndayizeye signed a peace deal with the main Hutu rebel group, the Forces for the Defence of Democracy (FDD). Its leader, Pierre Nkurunziza, joined the government as minister for good governance in December.
But a smaller Hutu rebel group, the Forces for National Liberation (FNL), rejected the deal and continued to attack government targets.
The government web site says President Ndayizeye's aims are peace, democracy and economic recovery. "I swear to work for the good of all Burundians, to fight genocide and exclusion," he said as he took the oath of office. And he has promised to organise elections.
Mr Ndayizeye is the seventh Burundi president and fourth Hutu president since independence in 1961. His three Hutu predecessors were all overthrown by the military. He is also vice-chairman of the main Hutu party, the Hutu Front for Democracy in Burundi (Frodebu).
President Domitien Ndayizeye
Exiled in Belgium 1972-1981
Worked as engineer in Rwanda 1981-1993
Returned to Burundi 1993
Elected to Frodebu steering comittee 1994
Jailed in 1995 on charges of arming rebels
Vice-president under Pierre Buyoya 2001-2003
Sworn in as president April 2003
Born to a peasant family in May 1953 in the northern province of Kayanza, he is married with six children. In 1972 he went into exile in Belgium. There he became active in politics, joining the Hutu Diaspora Movement and other groups set up to map out a "progressive" future for the country.
After graduating in engineering, Mr Ndayizeye left Belgium in 1981 and moved to Rwanda. Between 1982 and 1994 he held a senior position in NAHV-Rwanda/Burundi, a Dutch company selling Peugeot vehicles.
In 1993 he returned to Burundi, after Frodebu won multi-party elections. He was elected to the party's steering committee in 1994. In the same year he was appointed to senior positions in the National Security and Migration department.
But in 1995 he was arrested and jailed in Bujumbura central prison on charges of distributing arms to rebels. Many Tutsis believed him to be a rebel leader, while his Hutu colleagues insist he was a victim of persecution.
A senior Frodebu official told BBC Monitoring that President Ndayizeye has been deeply affected by his prison experience. The government web site points out that he has personally intervened in human rights cases, in particular those of journalists.
He was released in 1996, rearrested in 1997, then released again after President Buyoya's government came under national and international pressure to free political detainees. He was de facto leader of Frodebu from 1998 to 2001, while its president, Jean Minani, was in exile in Tanzania.
Both Mr Ndayizeye and Mr Minani took part in the Arusha peace talks of 1999 and 2000, which led to a ceasefire between the government and three Tutsi groups.
BBC Monitoring, based in Caversham in southern England, selects and translates information from radio, television, press, news agencies and the Internet from 150 countries in more than 70 languages.