J.K. Lasser's Your Income Tax 2013: For Preparing Your 2012 Tax Return

20.14 Travel Expenses of a Spouse or Dependents

Travel costs of a spouse, dependent, or any other individual who is not a business associate and who accompanies you on a business trip are not deductible unless that person is also your employee and has a bona fide business reason for taking the trip that would justify claiming a deduction if the person took the trip on his or her own.

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Filing Tip

How Much To Deduct for Spouse

If your spouse accompanied you on a business trip, your bills will probably show costs for both of you. These usually are less than twice the cost for a single person. To find what you may deduct where your spouse’s presence is for personal and not qualifying business reasons, do not divide the bill in half. Figure what accommodations and transportation would have cost you alone and deduct that. The excess over the single person’s costs is not deductible.

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Even though the travel costs of a non-employee spouse or other person are not deductible, you may deduct the cost of such person’s participation in the entertainment of business clients at conventions or business trips if the trip or entertainment meets certain tests (20.22). Generally, you may deduct the cost of goodwill entertaining of associates immediately before or after convention business meetings. A convention meeting qualifies as a bona fide business meeting. ...