Rwandan President Paul Kagame named the former labour minister Anastase Murekezi as the new prime minister on Wednesday, a presidential statement said.
The appointment is expected to bring in a possible cabinet reshuffle, as under Rwanda's constitution, ministers must be chosen -- or reappointed -- by the new prime minister.
"It is a great honour for me to have been appointed prime minister," Murekezi said on his Twitter account.
"My new appointment gives me a unique opportunity to keep serving my country Rwanda," he added.
Murekezi, who has served as the labour minister since 2008, is the fifth prime minister since the Rwandan genocide of 1994. He replaces Pierre Habumuremyi, who had held the post since 2011.
Murekezi, 62, married with two children, is a member of the Rwanda's second largest political party, the Social Democratic Party (PSD), a member of the ruling coalition.
He trained as an agronomist in Belgium.
Rwanda has shown dramatic economic successes in recent years, with its GDP per capita growing five-fold in the past two decades, according to the World Bank.
But critics accuses the country's authoritarian rulers of suppressing dissent and involvement in conflict in neighbouring Democratic Republic of Congo.