This study develops allometric equations for the estimation of aboveground liana biomass in field studies. We measured diameter length and total and leaf biomass of 561 shoots of 26 common liana species in secondary and primary forests of central Amazonia. Liana shoots ranged in size from 0.1 to 13.8 cm diameter and 20 cm–48 m length. We developed mixed-species and species-specific regressions. Goodness of fit of the allometric equations that emerged was similar whether diameter- or length-based (both R2=0.73 for mixed-species regressions). The diameter is therefore recommended as single biomass estimator. Using both diameter and length as estimators the R2 increased to 0.91 for mixed-species. Neither the forest type nor the number of shoots per plant individual affected the allometric relationships. With few exceptions species-specific equations were similar and goodness of fit increased only moderately over mixed-species equations. The mixed-species equations presented here were valid over a wide range of environments and species compositions and are recommended for the non-destructive estimation of liana biomass in tropical forests and bushlands.