Question:   Can an employer take out taxes if a Form W-4 was never filed?

Answer:   Yes, the employer is required to withhold income taxes. Chapter 9 of Publication 15, Circular E, Employer's Tax Guide, states that if an employee does not give you a completed Form W-4 (PDF), Employee's Withholding Allowance Certificate, withhold tax as if he or she is single, with no withholding allowances.

The employer is also required to withhold social security and Medicare taxes.