The title compound, C(3)H(2)Cl(3)N(3), crystallizes as the Z isomer with respect to the C=N bond. The -C(NH(2))=NCN functional group is effectively planar (r.m.s. deviation = 0.016 Å), with only the three Cl atoms out of the mol-ecular plane. A strong network of N-H⋯N hydrogen bonds forms dimers which are associated into ribbons in the crystal structure. Hydrogen bonding is suspected to be the cause of the near-equivalence of the formal C-N and C=N bonds (Δ(CN) = 0.008 Å).