Is the date that the medical procedure happened the date we go by or the date the invoice was paid?

According to Canada Revenue:

You can claim only eligible medical expenses on your return if you, or your spouse or common-law partner:

• paid for the medical expenses in any 12-month period ending in 2015
• did not claim them in 2014.

For more info, please see http://www.cra-arc.gc.ca/tx/ndvdls/tpcs/ncm-tx/rtrn/cmpltng/ddctns/lns300-350/330-331/menu-eng.html#...

Thank you for your question.

You need to put the total amount the year when this procedure happened.

You will need to amen the 2013 return:

You already filed your tax return, it was accepted by the CRA, and now you received additional forms or tax information or you need to correct something.

If so, you need to amend the tax return you already filed. First, be sure the return was accepted by the CRA, and do not change the return you already filed. Amended returns must be filed on a new form called T1-ADJ, T1 Adjustment Request.

Follow these steps:

1. Check that the CRA received your return
2. Follow these instructions to amend your return

Have a good day.