Thousands of teenagers are signing up to retake AS-level modules in January. One student at Farnborough sixth-form college, in Hampshire, resat 15 exams this summer to try to boost his B grades.
Critics say the resits option offered by the new system makes exams too easy to pass - the A-level pass rate this year rose by 4.5 per cent, nearly seven times last year's increase.
Estelle Morris, the Education Secretary, called last year for the number of January exams to be cut after schools said sixth-formers were sitting too many papers.
Even students who achieved good passes in this summer's exams are trying again because the rise in the number of A grade passes has made competition for elite university places even stiffer.
Qualifications and Curriculum Authority guidance on the reformed A-levels admits teachers are concerned that ubiquitous resits distract students from their work.
It advises schools to discourage those who have little chance of improving grades from resitting and suggests restricting the number of resits pupils can take in one go. Schools should put on extra classes for students who are re-entered, it said.
More than 50,000 exams were taken in January. Boards were initially surprised by the numbers until it became clear that most students were taking resits rather than first-time modules.
Resits this summer raised the number of AS entries to more than a million - a 25 per cent growth on 2001.
Students are supposed to be able to resit an AS module only once. However, while a second resit would not count towards their AS grade, it can count towards the overall A-level grade.
Also, if students do not accept their AS certification - known as "cashing in" - they can do the qualification again.
An exam-board insider said: "The resit situation has made things appallingly complicated both for exam boards and schools. The paperwork schools have to complete is devilish to cope with."
Some schools have banned January exams because they take up too much teaching time.
The deadline to enter for January resits is the end of October but entry numbers are expected to be greater than last year.