Some students had faced the prospect of retakes based on the new-style A levels - starting this September - which would include material not in their current courses. At least one exam board announced it would not offer re-sits.
But the exam-board regulator has insisted the pupils must be allowed to re-sit the old-style exams.
Boards had balked at the cost of providing exams based on the old syllabuses for only a tiny number of students.
But the exam regulator, the Qualifications and Curriculum Authority, has over-ruled the decision saying that the class of 2001 should not be disadvantaged by Government changes to the sixth-form curriculum.
Traditional A-levels disappear in September with the introduction of new-look modular courses which aim to encourage students to study a broader range of subjecs.
The current Year 12 students will be the last to study the old A-level syllabuses.
George Turnbull, spokesman for the Assessment Qualifications Alliance, confirmed the board had been forced to reverse its policy of not offering winter re-sits in 2001. He said the number of resits taken by students was "tiny", compared to AQA's 400,000 A-level entries. The Associated Examining Board normally had around 250,000 A-level entries and 660 candidates re-sitting, he said.
He said: "We will now be offering re-sit exams in line with the other boards. I would stress that only a few students take re-sits."
A QCA spokesman said: "We are still in negotiations with the awarding bodies.
"We want to see all the usual retakes being offered in 2001 because the students who started their courses in 1999 should not be disadvantaged in any way because of the changes."
But students who wish to re-take A-levels in summer 2002 or after must sit the new exams.