Lagomorphs are potentially important but understudied seed dispersers. In particular, there are no studies about the role of the Eastern Cottontail as a seed disperser. Therefore, the aim of this article is to evaluate the abundance and diversity of seeds dispersed by Sylvilagus floridanus in a conservation reserve within Mexico City. We collected fecal pellets during 2 periods, the highest seed production and the start of seed germination in the Reserva Ecológica del Pedregal de San Ángel. Pellets were subjected to different treatments to end seed dormancy (left in the field, stored in laboratory, and no treatment) and put to germinate in germination chambers and the field. We found that pellets left in the field had the most seeds germinating. Cottontails dispersed up to 0.77 seeds/g of excrete. A total of 15 species were observed, but the Chao estimator suggested that there were 29.8 species. Many of the dispersed seeds belong to rare species, most noticeable Jaegeria hirta. We conclude that cottontails are important dispersers due to the amount of excretes produced and the identity of the plants they disperse.