The School Leaving Certificate (SLC) examination started Monday from 7:30 a.m. local time (0215 GMT) till 10:30 a.m. (0515 GMT), Office of Controller of Examination (OCE) said.
"A total of 332,181 students are appearing in the SLC examination," OCE said in a press statement.
The students sitting the exams include 260,047 regular and 72, 134 from the exempted group, said the statement.
The OCE has fixed a total of 994 examination centers throughout the country.
A total of 40,304 manpower comprising 994 superintendents, 1, 988 assistant superintendents, 16,609 supervisors, 14,910 security personnel and 5,803 helpers are fixed for the SLC examination, said the statement.
Known as the iron gate of the students, the SLC examination will end on April 5.