Keith Rowley was sworn into office as prime minister of Trinidad and Tobago on Wednesday following his party's victory in Monday's general elections.
Rowley, a 65-year-old vulcanologist, led the People's National Movement (PNM) to victory when it won 23 of the 41 parliamentary seats in the oil-rich twin-island Caribbean nation.
The incumbent United National Congress/Congress of the People won 18 electoral seats and was ousted from power after one term in office.
Also taking the oath of office on Wednesday were Faris al-Rawi as the country's Attorney General and retired army major-general Edmund Dillon as Minister of National Security.
The rest of the Cabinet will be installed on Friday.
Rowley said the first order of business for his new government was getting the 2015/2016 oil-pegged budget passed in the Parliament which reopens in two weeks.
"The budget will take priority," he told reporters following his swearing-in ceremony.
During the elections campaigning, Rowley said falling oil prices will be a challenge and warned that there would be difficult times ahead for the country.