All John Hunter Hospital readmission data for October 1998 were examined. Twenty-four readmissions out of 3081 total admissions (0.8%) were defined as adverse events (unplanned readmissions) being nominally due to inappropriate medical management. The 24 adverse events comprised 5.5% of the 437 readmissions. A further five readmissions occurred because scheduled theatre was cancelled. Remaining readmissions were due to the condition of the patient in each case. Of the 16 highly preventable adverse events, 10 were allocated to the minor temporary category of severity. It is difficult to evaluate these readmission rates because there are no comparable findings in other Australian studies. The adverse events showed no particular association with patient age, sex, hospital of original admission or hospital specialty. While they were technically preventable, after medical record review a senior clinician identified these as extremely difficult cases, indicating that better outcomes may not have been possible.