Reports said most of the casualties were at the hotel in the city of Zamboanga to celebrate a local wedding.
The explosion blew the roof off the hotel and destroyed the upper levels, according to witnesses.
Officials blamed the Abu Sayyaf group - a small Islamic militant organisation with links to al-Qaeda.
THESE MONSTERS ARE EMULATING THEIR PROPHET.
THAT TELLS YOU EVERYTHING YOU NEED TO KNOW ABOUT ISLAM.