This guideline covers assessing and managing chronic hepatitis B in children, young people and adults. It aims to improve care for people with hepatitis B by specifying which tests and treatments to use for people of different ages and with different disease severities. In October 2017, we changed a footnote to update the information on UK marketing authorisations for entecavir. This guideline incorporates NICE technology appraisal guidance 153, 154, 173 and recommendation 1.1 of NICE technology appraisal guidance 96. These appraisals are still mandatory for the NHS in England.