The Cancer Information Service is a program of the National Institutes of Health (through the National Cancer Institute) that is provided to the United States of America public to provide personalized, confidential responses to specific questions about cancer. The CIS also provides help to those who wish to quit smoking.

The Cancer Information Service may be called directly through their 1-800 number, available from their website. CIS Information Specialists are also available through instant messaging, provided at the CIS homepage.