Unplanned readmissions of medical hospital patients have been increasing in recent years. We examined the frequency and associates of emergency medical readmissions to Galway University Hospitals (GUH).Readmissions during the calendar year 2006 were examined using hospital in-patient enquiry data. Associations with clinical and demographic factors were determined using univariate and multivariate analyses.The medical emergency readmission rate to GUH, after correction for death during the index admission, was 19.5%. Age 65 years or more, male gender, length of stay more than 7 days and primary diagnoses of chronic obstructive pulmonary disease, myocardial infarction, alcohol-related disease and heart failure during the index admission were significantly associated with readmission in univariate and multivariate analyses.The medical emergency readmission rate in GUH is comparable to other acute hospitals in Ireland and Britain. Further evaluation is needed to estimate the proportion of readmissions that are potentially avoidable.