Extrapair paternity and its correlates with breeding synchrony were examined in Gadwall (Anas strepera) using microsatellite DNA fingerprinting. Eleven of 261 ducklings (4.2%) within 8 of 29 broods (27.6%) had genotypes consistent with extrapair fertilizations, a comparable frequency to other species of waterfowl for which extrapair paternity has been documented. We found no evidence of intraspecific brood parasitism. The frequency of extrapair paternity was not significantly correlated with breeding synchrony. We suggest that female absences during egg-laying may have provided males with opportunities to pursue extrapair copulation when breeding was synchronous.