Caiman c. crocodilus constructed nests on small elevations in swamps during the long rainy season (May-July). Eggs were buried just beneath ground level and in addition covered by a small mound of dry leaves. This nest type is intermediate between the hole-type and the mound-type nest. Hatching occurred from the beginning until midway into the long dry season. One of two egg-containing nests studied was destroyed by predators. In the other nest 18 of 28 eggs hatched, which coincides with estimates based on pod sizes and estimated mean clutch sizes. Hatchlings stayed together (sometimes associated with second year caimans) for up to 18 months. Most of these pods were attended by an adult caiman for about seven months, until the beginning of the long rainy season. The sex ratio of newborn young was 0.5, but some pods seemed to consist of one sex only (sex ratio being 0 or 1). These results are compared with data on other populations of C. crocodilus and other crocodilians. In general there is a correlation between the nest type used and the nesting season; hole-nesting species nest in the dry season, whereas mound-nesting species usually nest in the rainy season. Nesting in the dry season by mound-nesting species occurs and possibly can be explained by avoidance of competition with sympatric moud-nesting species.