Mark Golding was appointed Opposition Leader at a ceremony at King's House Tuesday morning.
The Governor-General issued the instrument of appointment.
The member of parliament for St. Andrew South defeated Member of Parliament for St. Ann South East Lisa Hanna in Saturday's People's National Party presidential contest.
Hanna unable to attend
Ms Hanna was not present at the King's House ceremony.
A release from Ms Hanna's office said her absence was due to illness.
The statement said Ms Hanna was on Monday ordered by her doctors to stay home for the next four days due to a severe chest cold and sinus complications.
Miss Hanna said she informed Mr. Golding of her inability to attend the function after receiving the invitation Monday night.