A number of dignitaries including foreign diplomats were present during the oath-taking administered by President Ram Baran Yadav, Nepalnews.com reported. Regmi took over hours after Prime Minister Baburam Bhattarai resigned.
The choice of Regmi comes under an agreement among leaders of four major political parties. The agreement, signed late Wednesday, called for Regmi to have an 11-member Cabinet and requires the interim government, also called the Electoral Council of Ministers, to have elections by June 21 to choose a new Constituent Assembly.
The Constituent Assembly would be charged with completing a draft constitution for the Himalayan state, a task that has remained unfinished for years despite several deadline extensions.
Nepal had been a Hindu kingdom for more than 200 years before a decade-long Maoist-led rebellion, which ended in 2006 after the Maoists agreed to a peace process.
In elections in 2008, the Maoists won the largest number of seats in the assembly but didn't have a majority, leading to an impasse among the dozens of political parties and leaving the country without a draft constitution for electing a Parliament.
Notable deaths of 2014 [PHOTOS]
U.S., allies launch airstrikes against Syria