The biomass of old growth forests have been well studied around Manaus in the central Amazon compared to those at the other Amazonian regions. Castilho et al. (2006 in For Ecol Manage) suggested that the forest biomass increased with elevation in this region. Although the forests distributes from ca. 20 m to 160 m in elevation, the forest biomass has not been studied at a low elevation (< ca. 90 m) in this region. In the present study, 21 plots (60 x 60-m2) were established considering a wide range of elevation (ca. 40 – 130 m) around Manaus. In each plot, all trees whose diameters at breast height DBH > 10 cm were sampled. Small trees (5 < DBH < 10 cm) were also sampled within a subplot (20 x 60-m2) in each plot. For all sample trees, DBH were recorded. The DBH – tree height H relationship was also investigated for at least 30 individuals in each plot. The biomass was estimated with allometric model which was previously developed near the present study site. In this presentation, the relationship between topography and biomass will be discussed. The topographic information was obtained from the digital elevation file of SRTM data.