If you have only one telephone line in your home that is used for personal calls, then you may not deduct any portion of the standard monthly charge for your telephone. In such case, you may only deduct expenses for business-related long distance charges. If you install a second line strictly for business purposes, then you may deduct the base charge for that line. Voice mail communication services are deductible. Business use of mobile phones is also deductible, but you should keep track of business usage (name, number, minutes used) by the statements received from your cellular service provider. It is never a good idea to deduct 100% of cell phone charges, as everyone inevitably uses their phone to some extent for personal calls. You should not deduct 100% of your internet service either.