The profession needs valid, reliable and manageable instruments for assessing adult literacy and numeracy, and the National Research and Development Centre for Adult Literacy and Numeracy (NRDC) in particular needs such instruments for its own research programme. This report provides a review of existing assessment instruments. There had been no previous thorough review of adult literacy and numeracy assessment instruments used in Britain. A review was particularly opportune in 2002, when this project began, because several new instruments had appeared recently (the national tests of key/basic skills at Levels 1 and 2, the Basic Skills Agency’s Initial Assessment pack (2nd edition), Cambridge Training and Development’s Target Skills, the tests for the Skills for Life survey of adult basic skills needs being conducted in 2002/03). A total of 15 quantitative, summative instruments used to assess adult literacy and/or numeracy in Britain in the period 1991–2002 were identified, obtained and analysed. The analysis was carried out against a checklist and framework derived from theory, previous analyses, and the research team’s experience.