What is age discrimination? The Age Discrimination in Employment Act (ADEA) prohibits employers with 20 or more employees from discriminating against employees or applicants on the basis of age. Individuals must be at least 40 years of age to be covered by the ADEA. Harassment of employees on the basis of age is also unlawful discrimination. The Act also protects an older worker's disability payments, retirement incentives, life insurance, pension, and retirement plans. Amendments to the ADEA set out standards for waivers of legal rights by older employees in return for retirement incentives. Many states also have fair employment laws that prohibit age discrimination. Different age groups may be protected under state law and smaller employers may be subject to state requirements.