Coevolutionary theories of brood parasite strategy and host defense have been informed by research on egg mimicry and host recognition. However, there is no information on the strategies of New World parasitic cuckoos and their hosts. The striped cuckoo Tapera naevia is a New World cuckoo that uses multiple host species and maintains an egg color polymorphism. To investigate if color-matching influenced rejection behavior in hosts, I conducted an egg rejection experiment on a host that lays blue-green eggs, the rufous-and-white wren Thryophilus rufalbus and a host that lays white eggs, the plain wren Cantorchilus modestus. I used spectrophotometric analysis of egg color to determine the degree of egg color-matching. I found that at the field site the striped cuckoo lays highly mimetic eggs for the rufous-and-white wren, in both color and brightness. The rufous-and-white wren was more likely to accept mimetic artificial eggs than non-mimetic eggs. The plain wren exhibited low rejection rates for both mimetic and non-mimetic artificial eggs. The evidence from this study indicates that the striped cuckoo lays eggs that are closely color-matched to those of its preferred host, the rufous-and-white wren, and that this mimicry improves acceptance.