The huge writing burden on Leaving Cert students in the first week of the exam will be eased from next summer.
The new timetable will result in many of the heavier writing subjects being spread out over the course of the exams, instead of being "frontloaded" into the first few days.
Students, for example, will no longer be asked to take two "heavy" papers like geography and business on the one day.
In another change, each of the two papers in Irish, English and maths will be taken on different days.
The reforms were pushed through by the Minister for Education, Mary Hanafin, who has been critical of the intolerable burden placed on students in the first week of the exams.
However, the Minister has been forced to abandon her plan for a two-tier Leaving Cert, which would have seen English Paper 1 (featuring the essay and comprehension questions) taken on a Saturday morning in May. School managers claimed this would have put huge new pressures on schools.
Despite this setback, Ms Hanafin said the "new revised timetable is the most significant and student-centred reform of the exams timetable in decades".
Under the new timetable, most students will get at least one half-day without any exam in the first week.
Students taking both exams on the first day will also have their time spent in the exam hall shortened by 50 minutes, compared with recent years when the two English papers were taken.
Last night Ms Hanafin said: "While exams are always a test and an acceptable level of stress is a normal part of any testing procedure, I think the new timetable is very student-friendly.
The timetable changes were broadly welcomed by the teacher unions last night.
John White of the Association of Secondary Teachers, Ireland (ASTI), said: "Teachers have long been concerned by the level of stress placed on students by the frontloading of subjects involving lengthy essay-writing such as English, Irish and history.
"While this new timetable is to be welcomed, its impact will be reviewed and it is envisaged that the ASTI will be making proposals in relation to how it may be further improved."
Tim O' Meara of the Teachers' Union of Ireland fully endorsed "this positive change". But the union said the extra 20 minutes of exam time allowed in several subjects should only be available to special-needs students.
"In broader terms, we also need to look at reducing the writing time of many examinations.
"Perhaps we need to question if we are 'overexamining' students in some subjects with too many elements to some questions," he said.
