The title compound, [CoCl3(C10H14N3)], has slightly distorted tetrahedral geometry with monodentate coordination of the protonated ligand. The three Co-Cl distances are 2.2665 (7), 2.2615 (9) and 2.2712(10)Angstrom. The Co-N distance is 2.029(2)Angstrom. Antiparallel pairwise packing of molecules allows effective hydrogen bonding of the chloro ligands with both the benzimidazole N [3.439 (2) and 3.699 (2) Angstrom] and ammonium N [3.220(2) and 3.240(2)Angstrom] atoms. The respective Cl ... H separations are 2.76, 2.90, 2.29 and 2.47 Angstrom.