The Mexican Sheartail (Doricha eliza) is a hummingbird endemic to Mexico, where it occurs in disjunct populations in the states of Yucatan and Veracruz. In neither area has the species' reproductive biology been studied. On the basis of observations in Veracruz we characterize the species' eggs (the first description for the genus), fledging success, nestling growth, causes of mortality, nest-site selection, and courtship behavior. We located 11 active nests at various stages (8 eggs and 12 chicks, so not all nests contributed to all data sets). Nests were placed on four species of plants (three of them with spines), and some were aggregated. The species nested in natural grasslands and cattle pastures dominated by Acacia. Males formed leks. Chicks fledged from 4 of 11 nests, yielding 8 juveniles from 22 possible. Causes of mortality were predation, weather, human disturbance, and failure to hatch. Conservation of nesting sites in Veracruz is necessary for maintaining a healthy population.