Conductance of complexes bromopentammine cobalt (III) halides and perchlorate has been measured in water at different temperatures ( 250c ®350c ). The limiting equivalent conductance ( 0 L ) and ion association constant (KA) for complexes in water have been evaluated using Fuoss-Edelson equation. The influence of solvent on the solvation of ions has been discussed. Temperature variation of the association constant has been studied to evaluate the thermodynamic parameters