Your Professional Memberships should be included in the deduction section of TurboTax. The amount of union dues that you can claim is shown in box 44 of your T4 slips, or on your receipts and includes any GST/HST you paid. You can claim a tax deduction for these amounts on line 21200 on your tax return. If you’re the primary beneficiary of the union dues and your employer pays them on your behalf, you cannot claim a tax deduction, and you may have to pay taxes on this benefit.