This study estimated the above-ground biomass (AGB) of 1919 liana (195 spp.)\r\nwith a diameter =1 cm in 30 plots of 20×20 m (12 ha) located in ridges and valleys of the 50-ha plot of Forest Dynamic Project in Yasuni National Park. We estimated AGB with allometric equations obtained from the literature and with mean allometric equation developed in this study. We found no significant differences between the allometric equations except for the equation developed by Schnitzer et al. (2006). The ABG estimated with the mean allometric equation was 1502 t ha-1 which represents 52% of the total ABG estimated for the plot (273 t ha-1 of trees). We found no significant differences between the ABG estimated for ridges and valleys (744 t ha-1 and 758 t ha-1 respectively). Combretum laxum and Machaerium cuspidatum had the highest total ABG (31 t ha-1 y 14 t ha respectively). These two were also the dominating species in ridges and valleys.\r\nCombretaceae and Fabaceae were the dominating families in the 30 plots and in ridges and valleys. Some species showed a high ABG even though they were not abundant. For example with only one individual sampled in the ridge icranostyles ampla represented 15% of total ABG. This study represents the first estimation of liana ABG in Ecuador. On a global scale it is the first to analyze variations in ABG between topographic habitats. Furthermore it emphasizes the value of developing specific allometric equations for each region. Finally this study highlights the potential importance of lianas as carbon sinks.