An updated list of the Odonata of Costa Rica is presented containing 268 species. Since the last published list for the country, 41 additional species have been reported. The country is the best studied in Central America. The most species-rich families are Libellulidae, Coenagrionidae, Gomphidae, and Aeshnidae, together comprising ~75% of the total fauna. Most species in the country are also found in South America, indicating a tendency for wide ranges rather than endemism. However, about a fifth of the species appear to be endemic to the Costa Rica-Panama region. Estimates of the range of the proportion of total world species occurring in Costa Rica lead to predictions of a range of 5600-9000 species of Odonata worldwide.