This is the final version of the article. Available from the publisher via the DOI in this record. ; BACKGROUND: little is known about changes in the quality of medical care for older adults over time. OBJECTIVE: to assess changes in technical quality of care over 6 years, and associations with participants' characteristics. DESIGN: a national cohort survey covering RAND Corporation-derived quality indicators (QIs) in face-to-face structured interviews in participants' households. PARTICIPANTS: a total of 5,114 people aged 50 or more in four waves of the English Longitudinal Study of Ageing. METHODS: the percentage achievement of 24 QIs in 10 general medical and geriatric clinical conditions was calculated for each time point, and associations with participants' characteristics were estimated using logistic regression. RESULTS: participants were eligible for 21,220 QIs. QI achievement for geriatric conditions (cataract, falls, osteoarthritis and osteoporosis) was 41% [95% confidence interval (CI): 38-44] in 2004-05 and 38% (36-39) in 2010-11. Achievement for general medical conditions (depression, diabetes mellitus, hypertension, ischaemic heart disease, pain and cerebrovascular disease) improved from 75% (73-77) in 2004-05 to 80% (79-82) in 2010-11. Achievement ranged from 89% for cerebrovascular disease to 34% for osteoarthritis. Overall achievement was lower for participants who were men, wealthier, infrequent alcohol drinkers, not obese and living alone. CONCLUSION: substantial system-level shortfalls in quality of care for geriatric conditions persisted over 6 years, with relatively small and inconsistent variations in quality by participants' characteristics. The relative lack of variation by participants' characteristics suggests that quality improvement interventions may be more effective when directed at healthcare delivery systems rather than individuals. ; This work was supported by the National Institute for Health Research (NIHR) Health Services and Delivery Research Programme (grant number HS&DR Project 10/ 2002/06). The ELSA was funded by the US National Institute on Aging and UK government departments. The funders had no role in the study design, data collection, data analysis, data interpretation, writing of the report or decision to submit the article for publication.