We investigated the distinctiveness of males' song and the relationship between song variables and females' mate choice in the Golden-winged Warbler (Vermivora chrysoptera). We recorded the songs of 23 males and quantified them to examine performance-related traits and specific song content. We carried out discriminant function analysis to compare variation within and among males for characteristics of both song types I and II. We used microsatellite DNA to identify the parents of 62 nestlings from 17 nests. By assigning paternity to males in our population we could examine relationships between females' choice and variation in males' song by comparing characteristics of within- and extra-pair sires. While we were able to discriminate statistically between individual males' songs, we found no significant differences in song variables between the within- and extra-pair males at a given nest. Therefore, female Golden-winged Warblers do not appear to be using these differences in song in choosing a mate. Further research on the Golden-winged Warbler is needed to understand song function and to gain insight into this species' reproductive biology, both of which could have important conservation implications for this declining species.