If you have chosen to incorporate your business, you must file and pay federal income taxes, and, in many cases, state and local income taxes as well.
If you are a C Corporation, you will pay income taxes on income left over after business expenses. These taxes are calculated on a sliding scale that usually increases as your income rises. You may also be liable for other taxes, such as personal-holding-company taxes and the accumulated-earnings tax. You should consult with your tax advisor to see exactly what corporate income taxes apply to your company.
If you are an S Corporation, your company, in most cases, will not pay direct taxes. Instead, the income or loss is passed on directly to the shareholders, who pay the tax at the personal rate. Be aware that some states do not recognize S corporation status and tax the company directly.
No matter what kind of corporation you are, your federal corporate returns are due a month prior to personal income tax returns -- the fifteenth day of the third month after the company's fiscal year ends. So, if your year ends on December 31, your tax return is due March 15, instead of April 15. Corporate estimated taxes are due on the 15th day of the fourth, sixth, ninth, and twelfth month after the end of the fiscal year. For a year ending on December 31, that would be April 15, June 15, September 15, and December 15.