We report the first description of the nest, eggs, and nesting phenology of the Cozumel Vireo (Vireo bairdi), a passerine species endemic to Isla Cozumel, México. We discovered three nests of this species in 2009. These open-cup nests were woven onto branches and hung beneath forks. Clutch size was 2–3 eggs, and eggs were ovate and had a white ground color with reddish-brown flecks. These characteristics of nests and eggs are similar to those of most other Vireo spp., including other West Indian members of the Vireo subgenus. Breeding activities, including egg-laying, incubation, and nestling and post-fledging provisioning occurred from May to July 2009. We estimated the length of incubation to be ∼14 days and length of the nestling stage to be 11–12 days. Much of the Cozumel Vireo's breeding biology remains unknown and further study of this single-island endemic is needed.