Techniques to stimulate cognition in older people with dementia are widely used around the world. The RCT by Spector et al., compared 7 weeks of a twice-weekly cognitive stimulation therapy group with treatment as usual for older people with dementia showed the intervention group improved on cognition and quality of life. The presentation includes the 2012 Cochrane review by Woods et al., which looked at randomised controlled trials (RCTs) of cognitive stimulation as an intervention for dementia from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group. Cognition improved on the ADAS-Cog and cognitive stimulation also improved depressive symptoms and quality of life. We used qualitative methods both to refine the CST package, and to investigate the experiences of the people attending CST groups, their carers and the group facilitators. Themes identified in the analyses were positive experiences of being in the group and changes experienced in everyday life providing evidence for the mechanisms of change. New results will be presented from the current long term study in 238 people with dementia involved in CST groups. Cognitive stimulation approaches improve cognition in people with dementia but many approaches remain somewhat unstandardised in terms of length and intensity of treatment. Training and manualisation of approaches should improve the delivery of treatment.