At least 1,415, 315 candidates on Monday began their KCPE exams,
It is the last KCPE exam to be done in the country after 38 years of its implementation.
The ministry is replacing the 8-4-4 curriculum with the Competency-Based Curriculum which is a 2-6-6-3 system.
On Monday, the candidates sat for the Mathematics, English and composition papers.
Before entering the examination roos, the candidates were subjected to a search, where the invigilators were to check on unnecessary and unwanted items.
Some candidates wrote their papers in hospitals while some were in prison.
President William Ruto officiated the beginning of the exams at Kikuyu Township Primary School.
He urged the pupils sitting for the Kenya Certificate of Primary Education (KCPE) and Kenya Primary School Education Assessment (KPSEA) examinations to do their best.
Passing a message of encouragement, the President told the students to remain confident as they entered the examination rooms.
"To all candidates who are doing this exam today, I wish you all the best and success in these exams. As you go into the exam room know that you are not alone so be confident, do your best," Ruto said on Monday.
The KCPE and KPSEA exams commenced on Monday, October 30, and are set to conclude on Wednesday, November 1.
A total of 1,282,574 candidates are participating in the KPSEA assessments.
The KAPSEA assessment will be done to monitor learner achievement and not the placement of candidates.
Unlike in KCPE exams where candidates are rated out of 100 per cent, KPSEA only accounts for 40 per cent of the final score.
The other 60 per cent comes from classroom-based continuous assessment tests conducted in Grades 4, 5 and 6.
They are also tested in Creative And Social Sciences (C.A.S.S) which includes Arts and Crafts, Music, Social Studies, and Religious Education.