The allometric equation for turi leaves (Sesbania grandiflora) is not yet available, even though this special equation can be used to calculate forest values. The purpose of this research was to determine the allometric equation of turi leaves. Twenty tree individuals scattered in four diameter classes (0 - <5 cm, 5 - <10 cm, 10 - <15 cm, 15 - <20 cm) were cut down. The wet weight of the leaves of each tree was measured. A number of leaves were taken and sampled. From each tree three samples were taken as replicates. Wet weight and dry weight were measured. Dry weight was obtained after each leaf sample was dried in the kiln oven for 24 h at 105 oC. The water content of the leaves and the allometric equations was determined. The higher the diameter class, the lower the moisture content. Conversely, the higher the diameter class, the larger the biomass of turi (spesifically its leaves). A good allometric equation is used to estimate the dry weight of turi leaves growing in the stem diameter (measured at breast height) up to 20 cm is DW = 0.0002 D 3,3559.