The National Assembly in Laos has formalised the appointment of a new president, prime minister and cabinet.
Mr Bouasone's appointment is unlikely to bring significant reform
Bouasone Bouphavanh was appointed prime minister, replacing Boungnang Vorachit, who became a vice-president.
Choummaly Sayasone was named president, in place of Khamtay Siphandone, who stepped down as leader of Laos' only political party in March.
The new line-up was unlikely to herald significant reform in the communist country, analysts say.
Mr Bouasone told the lawmakers that he would maintain economic growth and fight corruption.
The National Assembly was meeting for the first time since elections in April in which the ruling Lao People's Revolutionary Party won all but one parliamentary seat.
Laos has been ruled by a communist government since an American-backed government fell in 1975.
A mainly agricultural country of 5.9 million people, Laos is one of Asia's poorest nations.