No. In fact, it may be advantageous to deduct RRSP contributions in a future year in which you are in a higher tax bracket. As an example, in 2003, you may be a student in the lowest tax bracket and make an RRSP contribution. If you graduate and are employed full-time in 2004, your income may take you to a higher tax bracket in 2004. By deducting your 2003 RRSP contribution in 2004, you would then be eligible for increased tax relief because you could recover tax that would otherwise be paid at a higher rate.

You should still report your 2003 RRSP contributions on your 2003 tax return (as a carry-forward), even if the deduction won't be used until 2004. Your 2003 contribution can be earning tax-deferred income for you, while you are deferring the tax deduction until a future year in which you can recover more tax.