BACKGROUND: This study examined the agreement between patient-reported chronic diseases and hospital administrative records in hip or knee arthroplasty patients in England. METHODS: Survey data reported by 676,428 patients for the English Patient Reported Outcome Measures (PROMs) programme was linked to hospital administrative data. Sensitivity and specificity of 11 patient-reported chronic diseases were estimated with hospital administrative data as reference standard. RESULTS: Specificity was high (> 90%) for all 11 chronic diseases. However, sensitivity varied by disease with the highest found for 'diabetes' (87.5%) and 'high blood pressure' (74.3%) and lowest for 'kidney disease' (18.8%) and 'leg pain due to poor circulation' (26.1%). Sensitivity was increased for diseases that were given as specific examples in the questionnaire (e.g. 'parkinson's disease' (65.6%) and 'multiple sclerosis' (69.5%), compared to 'diseases of the nervous system' (20.9%)). CONCLUSIONS: Patients can give information about the presence of chronic diseases that is consistent with chronic diseases derived from hospital administrative data if the description in the patient questionnaire is precise and if the disease is familiar to most patients and has significant impact on their life. Such patient questionnaires need to be validated before they are used for research and service evaluation projects.