A species-specific primer set has been developed and used with a preamplification and multiplex PCR method for molecular sexing from the faeces of the vulnerable Chinese egret (Egretta eulophotes). This new assay produced one common fragment in both females and males (approximately 230 bp) and one specific fragment in females (about 136 bp). A highly efficient sex identification result (97.7%, 171/175 faeces samples) and great versatility on seven other ardeid species suggests that this improved molecular approach is a sensitive sexing tool for the Chinese egret and other ardeid species. It will facilitate further studies on their population sex structure using non-invasive genetic samples.