Ethiopia's new leader, Hailemariam Desalegn, has been sworn in after the death of long-time leader Meles Zenawi in August.
"I am very happy to take the responsibility of being prime minister," said Mr Hailemariam, 47, as lawmakers banged on their desks in support, AFP news agency reports.
Mr Hailemariam had been deputy prime minister and foreign minister.
Mr Meles died last month in Brussels after 21 years in power.
He had been praised for bringing economic growth to Ethiopia but criticised for not tolerating opposition.
He was also a key Western ally in the volatile Horn of Africa - twice sending troops into neighbouring Somalia to tackle Islamist groups.
Mr Hailemariam was last week chosen to head the governing Ethiopian Peoples' Revolutionary Democratic Front (EPRDF).
He vowed to continue Mr Meles' "legacy without any change".
"We brought peace, democracy and development to the country," he said.