It depends on how your business is formed. If you're a sole proprietor, selfemployed, then you don't have to file two returns; however, suppose you have a business and you're a sole proprietor, meaning you're not incorporated, you would report the results of your operations, your income and expenses, on a Schedule C with your federal tax return. In general, you do have to account for your business income and expenses separately, and that inclusion is with the personal tax return. If you're self-employed and you have a separate business entity like a partnership, a limited liability company, or corporation, you'll generally have to file a separate return for that entity. Tax returns of partnerships and LLCs are usually due by April 15th while corporations are generally due March 15th.