Single crystals and powder samples of Co analogue of paganoite CoBiO(AsO4) have been obtained by high-temperature solid-state reactions. Crystal structure [triclinic, $$P\bar{ 1 }$$ P 1 ¯ , a = 5.2380(3), b = 6.8286(4), c = 7.6150(4) Å, α = 111.631(2), β = 108.376(2), γ = 108.388(2)°, V = 209.55(2) Å3] has been refined to R 1 = 0.018 on the basis of 1524 unique observed reflections. CoBiO(AsO4) is isotypic to paganoite, NiBiO(AsO4). The crystal structure can be described as based upon [OCoBi]3+ chains of edge-sharing (OBi2Co2) tetrahedra linked via (AsO4) groups. Differential thermal analysis reveals no phase decomposition till 850 °C, when the compound starts to melt. A small endothermic peak is observed near 330 °C. Thermal expansion has been studied by high-temperature powder X-ray diffraction. Thermal expansion coefficients (α a = 10.1 × 10−6, α b = 12.6 × 10−6, α c = 10.5 × 10−6 K−1) indicate a relatively isotropic behavior with the less intense expansion direction parallel to the direction of the chains of oxocentered tetrahedra. Magnetic susceptibility of CoBiO(AsO4) reveals the presence of an antiferromagnetic ordering at T N = 15.4 K.