We analyzed the structure and variation of the songs of the Brownish-flanked Bush Warbler (Cettia fortipes), a species common in southeastern Asia, including southwestern China, site of our study. During the breeding season of 2009, we investigated the possibility of distinguishing individuals by song. Most Brownish-flanked Bush Warblers we studied had a unique song repertoire composed predominantly of two song types. Whether singing spontaneously or in response to playback, the birds deliver the two types alternately. We defined type alpha as a song consisting of two notes, type beta as a song consisting of three notes. Both song types varied from individual to individual. Discriminant analysis revealed that the songs of individual Brownish-flanked Bush Warbler songs were distinct; rates of correct classification were 98% for the alpha song and 99% for the beta song.