A life interference measure specifically designed for young adults with anxiety and depressive symptoms does not currently exist. This paper describes the development and psychometric evaluation of a brief self-report measure of life interference associated with young adult anxiety and depression, the Child Anxiety and Depression Life Interference Scale - Young Adult version (CADLIS-YA). Cross-sectional, correlational and exploratory factor analysis (EFA). Five-hundred and thirty-two participants aged 18-24 years recruited from an undergraduate and community sample completed the CADLIS-YA. An EFA supported a three-factor model describing the impact of young adult anxiety and depression on social life, family and daily life interference. Test-retest reliability and internal consistency were good to excellent. Convergent validity was demonstrated, and the scale differentiated between young adults with and without elevated anxiety and depressive symptoms. Support for divergent validity was limited. The CADLIS-YA is a reliable and valid life interference measure for young adults with symptoms of anxiety and depression. It is potentially suitable for administration in low-resource research settings and it has promise for use in clinical settings; however, it needs validation in a clinical sample.