This study of 521 encounters in 25 urban general practices in Australia, compares both patient and doctor reported reasons for encounter (RFE) and diagnoses. Although doctors and their patients generally agreed on the overall distribution of RFE and diagnoses that arose, there was disagreement in at least 30% of paired comparisons within individual encounters. There was better agreement for RFE than for diagnoses. This may have been partly due to differences in the classification systems used. However, it suggests that diagnoses recalled by patients at later household interview are at best only a rough approximation of the diagnoses recorded by the doctor. These findings are important both for patient care and for the conduct of general practice morbidity research.