Magnetic susceptibility, electrical resistivity, thermopower, specific heat, and thermal conductivity measurements were made on Ce 2 NiB 10-δ . The crystal structure is derived from that of CeB 6 by replacing two B atoms in the B 6 –B 6 network with one Ni atom. The sample prepared by arc melting is deficient in the boron composition, \(\delta\cong 0.3\). The magnetic susceptibility, electrical resistivity, and specific heat show no sign of magnetic ordering down to 0.5 K, but exhibit non-Fermi liquid (NFL) behavior, i.e., χ∝- T 0.5 , ρ∝ T and C / T ∝-ln T . This behavior of C ( T ) in zero field and its suppression by external magnetic fields are explained qualitatively by the Kondo disorder model with the average Kondo temperature of 26 K. Atomic disorder induced by boron defects is the most probable origin of the NFL behavior. The thermal conductivity of Ce 2 NiB 9.7 is much reduced from that for CeB 6 , which is ascribed to the increase of phonon scattering by the lattice defect.