Can employment applications request an applicant's Social Security number?

While not unlawful to request an applicant's SSN, due to identity theft and general privacy concerns, employers generally should not request this information on an employment application form as an employment application is often viewed by individuals who do not have a need to know this information. An employment application should request only information directly related to an applicant’s ability to perform a specific job. As a general practice, employers should request SSN information only when absolutely necessary, e.g., in conjunction with a background check, completing a W-4, or when enrolling the employee into benefits plans. This information should be requested separate from the employment application, and safeguards should be in place to protect and keep this information confidential. Employers should also implement procedures for safe disposal of this information once an employment decision has been made. (Society for Human Resource Management)