Stems of 4348 lianas from 12 subsampled 1 ha plots in Yasuni Ecuador represented more than 311 species of climbing woody plants. The plots (each 0.2 ha in area) which individually included up to 106 species among 314 stems were established in the Huaorani Ethnic Reserve and Yasuni National Park and represent terra firme and floodplain habitats. Yasuni is one of the richest areas sampled for liana diversity in the neotropics. A relatively small group of species (38) comprise the dominants in this forest as defined by species contributing consistently to 50% of all stems to samples from either habitat. Distance-related diversity (i.e. beta) is low across both spatially adjacent and distant plots. Floodplain habitats show a slightly higher decay of similarity with distance than either terra firme habitats or cross-habitat comparisons. Cross-habitat comparisons are significantly less similar than same-habitat comparisons at all distances. Habitat-related beta diversity probably contributes to total richness in Yasuni although abundant liana species in Yasuni rarely show absolute restriction to one habitat or the other. A comparison of these data to other sampled sites in the neotropics highlights the problems inherent in comparisons among areas sampled by different methods.