The faunal composition, richness, and their determinant factors were analyzed in a Mediterranean temporary pond located in NE Spain. The aquatic community was sampled weekly over 7 periods of flooding during 4 years (1996–1999). Composition of the pond community was found to be influenced by duration of the hydroperiod and, secondarily, by seasonality. Insects and crustaceans were the most well-represented types of fauna. The small numbers of species captured over all hydroperiods spend the dry periods in situ or have an important dispersal capacity. Comparison of the faunal composition of several temporary ponds of temperate latitudes confirms the great diversity of faunal groups found in temporary aquatic environments, and this richness is comparable to that found in permanent water bodies. The richness of these temporary ponds is related to flooded surface and to hydroperiod duration. The peculiarity of the fauna of temporary waters, together the deteriorating condition of those habitats, make it necessary for more active policies of preservation to be pursued.