OBJECTIVE. To validate the Hong Kong Accident and Emergency Triage guidelines. DESIGN. Retrospective chart review. SETTING. The Accident and Emergency Department of a tertiary hospital in Hong Kong. PARTICIPANTS. Patients who attended the Accident and Emergency Department on one day in February 2012. MAIN OUTCOME MEASURES. The inter-rater reliability in two pairs of nurses grouped according to experience and validity as compared with an expert panel. RESULTS. Of the 100 patients recruited and triaged into levels 1 to 5, the weighted kappa coefficient (inter-rater reliability) for the two pairs of nurses was 0.699 and 0.717, respectively. The weighted kappa coefficient for validity was 0.766. When only patients in triage levels 3 and 4 were included, the weighted kappa coefficient for reliability dropped to 0.632 and 0.585, respectively. The weighted kappa coefficient for validity also decreased to 0.558. CONCLUSIONS. The overall inter-rater reliability and validity of the Guidelines appeared acceptable. Further revision of the Guidelines on triaging patients to levels 3 or 4 is probably necessary.