How do i claim repayment of money to employer from previous year

[thekeanes]

I have a letter from employer stating that I have repaid an amount that was overpaid to me last year (2015 tax year)

[Delphision · Accepted solution]

You need to file a T1 adjustment to reduce your income in 2015 and potentially get a bit of a refund.  You cannot deduct it in this current year.

http://www.cra-arc.gc.ca/E/pbg/tf/t1-adj/README.html