We studied Chestnut-sided Warblers (Dendroica pensylvanica) to determine whether there exists any relationship between plumage coloration and reproductive success in this species. We observed that males with more extensive chestnut breast coloration initiated nests significantly earlier than males with less chestnut, and had marginally larger clutch sizes as well. However, there was no significant relationship between the number of young fledged or the condition of the young and the extent of chestnut breast coloration, nor were there any significant relationships between any of these measures of reproductive success and the extent of yellow crown coloration. The extent of chestnut coloration on the breast was significantly less for males in their first breeding season, suggesting that the relationships between the extent of breast coloration and reproductive success may reflect age specific differences in these parameters.