In a 75-53 vote by CAR lawmakers, Catherine Samba-Panza replaced interim leader Michel Djotodia, who resigned under pressure Jan. 10, Voice of America reported.
Meeting in Brussels, EU foreign ministers approved a plan to send peacekeeping troops to support 1,600 French soldiers and 5,000 African troops already in CAR.
The United States also pledged to provide $30 million more in humanitarian aid.
Sectarian conflict in the country began last year after President Francois Bozize was ousted by Muslim Seleka rebels.
At least 22 people died outside the town of Bouar Friday, the aid group Save the Children said, when a convoy of Muslims fleeing the conflict were attacked.