Monks, nuns and other Buddhists lit candles and performed rites at Odong Mountain, where it is believed three bones of Buddha are buried, The Phnom Penh Post reported.
An official at the National Committee for Organizing National and International Festivals said two supreme monks led Monday's ceremony.
Meak Bochea isn't as widely celebrated as Visaka Bochea, Buddha's birthday, but is still an important holiday for devout Buddhists, the Post reported.
"According to the mythology, Meak Bochea was the day Buddha predicted and announced the date he would attain enlightenment and enter into nirvana," Ang Choulean, an ethnologist at the Royal University of Fine Arts, said.
Notable deaths of 2014 [PHOTOS]