This survey was designed to study the problem of hospital readmission in a geriatric centre in Hong Kong. A retrospective survey of 565 unplanned admissions to a geriatric department showed that the rate of unplanned readmission was 25.3%. Only 56.7% of the selected hospital records could be retrieved for further analysis. Of the unplanned readmissions, 19% were potentially avoidable. The reasons for readmission included medication problems (2.5%), inadequate medical management (16.5%), natural clinical course (32.9%), and new clinical problem (48.1%). A statistical difference was found in the readmission rates for those patients with or without multiple admissions in the previous year (P = 0.001). Those patients who presented with cardiovascular problems were also more likely to be readmitted, although this difference was not statistically significant.