OBJECTIVE: To investigate the relation between older patients' assessments of the quality of their primary care and measures of good clinical practice on the basis of data from administrative and clinical records. DESIGN: Cross sectional population based study using the general practice assessment survey. SETTING: 18 general practices in the Basildon primary care trust area, south east England. PARTICIPANTS: 3487 people aged 65 or more. MAIN OUTCOME MEASURES: Correlations between mean practice scores on the general practice assessment survey and three evidence based measures on survey of case records (monitoring for, and control of, hypertension, and vaccination against influenza). RESULTS: 76% of people (3487/4563) responded to the general practice assessment survey. Correlations between patient assessed survey scores for technical quality and the objective records based measures of good clinical practice were 0.22 (95% confidence interval -0.28 to 0.62) for hypertension monitored, 0.30 (-0.19 to 0.67) for hypertension controlled, and -0.05 (-0.50 to 0.43) for influenza vaccination. CONCLUSIONS: Older patients' assessments are not a sufficient basis for assessing the technical quality of their primary care. For an overall assessment both patient based and records based measures are required.