A Gram-negative, facultatively anaerobic, chemo-organotrophic, non-pigmented, slow-growing bacterium was isolated from acidic Sphagnum peat and designated strain TPB6017T. Cells of this strain were long rods that multiplied by normal cell division and were motile by means of a single flagellum. Cells grew under reduced oxygen tension and under anoxic conditions and were able to ferment sugars and several polysaccharides, including amorphous and crystalline cellulose. Strain TPB6017T was a psychrotolerant acidophile capable of growth between pH 3.0 and 7.5 (optimum 4.5–5.0) and at 4–35 °C (optimum 20–28 °C). It was extremely sensitive to salt stress; growth was inhibited at NaCl concentrations above 0.1 % (w/v). The major fatty acids were iso-C15 : 0 and iso-C17 : 1ω9c; the polar lipids were phosphatidylethanolamine and a number of phospholipids and aminophospholipids with an unknown structure. The quinone was MK-8. The DNA G+C content was 57.6 mol%. Comparative 16S rRNA gene sequence analysis revealed that strain TPB6017T was a member of subdivision 1 of the phylum Acidobacteria and belonged to a phylogenetic lineage defined by the acidophilic aerobic chemo-organotroph Acidobacterium capsulatum (92.3 % sequence similarity). However, cell morphology, type of flagellation, the absence of pigment, differences in fatty acid and polar lipid composition, possession of a cellulolytic capability, inability to grow under fully oxic conditions and good growth in anoxic conditions distinguished strain TPB6017T from A. capsulatum. Therefore, it is proposed that strain TPB6017T represents a novel acidobacterium species in a new genus, Telmatobacter bradus gen. nov., sp. nov.; strain TPB6017T ( = DSM 23630T = VKM B-2570T) is the type strain.