I think most of the replies here are far too conservative, and assume that CRA restricts the deduction of tax preparation fees far more than is actually so. What is reasonable is always debatable, but once the return includes business, professional, commission, rental, or investment income, it is arguable that the taxpayer should engage professional assistance. It is also arguable that once a taxpayer engages a professional preparer, it is reasonable to have that person prepare the whole return (and, I would further argue, those of the spouse or common-law partner and dependants) not just one or two schedules. The following are some excerpts from CRA’s website (I will not go into fees for representation in an audit or appeal, which are clearly deductible):
Re T1 line 22100:
Claim the following carrying charges and interest that you paid to earn income from investments:
[R]easonable fees, that have not already been deducted, to have someone prepare or assist you in filing your return if you have income from a business or property (see consolidated and archived Interpretation Bulletin IT-99R5, Legal and Accounting Fees)
[Also see the definition of property in subsection 248(1) of the Income Tax Act. - K]
From IT-99R5:
Income Tax Returns
Reasonable fees and expenses incurred for advice and assistance in preparing and filing of returns for income tax purposes are normally deductible by virtue of section 9 and are not limited under paragraph 18(1)(a) in computing business or property income to which such tax returns relate. A taxpayer who is employed in connection with selling property or negotiating contracts and who is entitled to deduct expenses pursuant to paragraph 8(1)(f) (see the current version of IT-522, Vehicle, Travel and Sales Expenses of Employees), may deduct a reasonable amount paid during the year to comply with the requirement to file an income tax return.
Re T776 line 8860:
You can also deduct expenses you had for bookkeeping services, audits of your records and preparing financial statements. You may be able to deduct fees and expenses for advice and help to prepare your income tax return and any related information returns.
Re T2125 line 8860:
Line 8860 – Professional fees (includes legal and accounting fees)
Deduct the fees you incurred for external professional advice or services, including consulting fees.
You can deduct accounting and legal fees you incur to get advice and help with keeping your records. You can also deduct fees you incur for preparing and filing your income tax and GST/HST returns.