Previous authors have noted the unique singing behavior and apparently large song repertoires of male Yellow-breasted Chats (Icteria virens). We studied the singing behavior of 10 male chats in central Kentucky in an attempt to determine the size and functions of their song type repertoires and examine possible relationships among singing behavior, morphological characteristics, and reproductive success. During the 1995 breeding season, we recorded and analyzed chat songs and determined the morphological characteristics and reproductive success of focal males. Repertoire sizes varied among male chats, ranging from 46–81 song types. Larger males (as determined by tarsus length) had larger song type repertoires, and males with longer wing chords fledged more young. These relationships suggest a correlation between male quality (as determined by size and reproductive success) and repertoire size. Male chats spent less time singing after pairing, suggesting that singing plays a role in mate attraction. However, singing by male chats likely serves other functions, such as territorial defense and attracting additional mates, because males continued singing after pairing. In contrast to male wood-warblers (Parulidae), male chats have relatively large repertoires of song types and also vary the sequence of song types, the frequency of repetition of individual song types, and the length of time between consecutive song types. Such differences in singing behavior lend support to the hypothesis that chats are not parulids.