Some 66,800 students, who failed the national high school graduation exam in August, sat for the test for the second time on Monday, officials said.
"The candidates are taking the exam at 177 centers with 2,752 rooms throughout the country," said Ros Salin, spokesman for the ministry of education, adding that the results of the two-day test will be released on Nov. 4.
The students take the exam in the subjects of chemistry, biology, history, foreign language, Khmer literature, physics, and mathematics, according to the ministry's announcement.
The high school graduation test is a prerequisite for students to pursue their studies in university levels.
To prevent bribery and cheating during the exam, the ministry of education has cooperated with the government anti-corruption unit to deploy 3,180 anti-corruption officials and volunteers at all exam centers, said Kheang Seng, vice-president of the unit.
In the first exam in August, only 23,126 applicants, or 25.72 percent, of the total 89,937 candidates passed their high school graduation test.