A CIS (Construction Industry Scheme) card is a type of identification card that is issued to workers in the construction industry in the UK. The CIS card is issued by the HM Revenue and Customs (HMRC) and is used to verify an individual's employment status for tax purposes.

Workers in the construction industry are divided into two categories for tax purposes: CIS deductions workers and CIS non-deductions workers. CIS deductions workers are employees or workers who are paid gross and have tax and National Insurance contributions deducted from their pay, while CIS non-deductions workers are self-employed and are responsible for their own tax and National Insurance contributions.

CIS cards are important for workers in the construction industry, as they are used to verify employment status and ensure that the correct tax and National Insurance contributions are paid.