Hexakis(mu-2-aminoethanethiolato)-1kappa3N,1:3kappa6S;2kappa3N,2:3kappa6S-dicobalt(III)nickel(II) dichloride trihydrate, [Co2Ni(C2H6NS)6]Cl2.3H2O, M(r) = 758.4, triclinic, P1BAR, a = 13.624 (3), b = 13.943 (3), c = 8.205 (2) angstrom, alpha = 101.29 (1), beta = 90.08 (1), gamma = 69.14 (2)degrees, V = 1424.3 (6) angstrom3, Z = 2, D(x) = 1.77 g cm-3, lambda(Mo Kalpha) = 0.70930 angstrom, mu = 23.5 cm-1, F(000) = 784, room temperature, R = 0.035 for 4379 independent reflections [F(o) > 3sigma(F(o))]. The Ni atom is coordinated octahedrally by six thiolato S atoms from two fac(S)-[Co(C2H6NS)3] subunits, forming a linear-type S-bridged Co(III)Ni(II)Co(III) trinuclear structure.