IRS, 941 and You! From IRS.gov General Instructions: Understanding Form 941 Purpose of Form 941 These instructions give you some background information about Form 941, Employer's QUARTERLY Federal Tax Return. They tell you who must file the form, how to fill it out line by line, and when and where to file it. If you want more in-depth information about payroll tax topics relating to Form 941, see Pub. 15 (Circular E), Employer's Tax Guide, or visit the IRS website at www.irs.gov and type 'Employment Tax' in the Search box. Federal law requires you, as an employer, to withhold taxes from your employees' paychecks. Each time you pay wages, you must withhold - or take out of your employees' paychecks - certain amounts for federal income tax, social security tax, and Medicare tax. Under the withholding system, taxes withheld from your employees are credited to your employees in payment of their tax liabilities. Federal law also requires employers to pay any liability for the employer's portion of social security and Medicare taxes. This portion of social security and Medicare taxes is not withheld from employees. Use Form 941 to report: payroll taxes (withheld federal income tax and both employee and employer shares of social security and Medicare taxes) for the quarter; current quarter's adjustments to social security and Medicare taxes for fractions of cents, sick pay, tips, and group-term life insurance; and prior quarters' adjustments to payroll taxes (attach Form 941c). Do not use the Form 941 to report backup withholding or income tax withholding on nonpayroll payments such as pensions, annuities, and gambling winnings. Report these types of withholding on Form 945, Annual Return of Withheld Federal Income Tax.