The kinetics of the redox reactions of 2,6-dichlorophenol indophenol (DCPIP) by metabisulphite ions (S2O5 2- ), sulphite ions (SO3 2- ), hydrazine (N2H4) and hydrogen peroxide (H2O2) at 28 Â± 1 Â°C was studied at Î»max of 600 nm in aqueous medium under pseudo-first order conditions at I = 0.2 mol dm-3 (NaCl). The stoichiometry of 1:1 was obtained for all the reactions except DCPIP - S2O5 2- which was 2:1. The reactions were first order in [S2O5 2- ], [N2H4], [H2O2] and zero order with respect to [SO3 2- ]. The reactions conform to the following rate equations: d[DCPIP]= k2 [DCPIP] [S2O5 2- ] dt where k2 = 16.24 Â± 0.03 dm3 mol-1 s -1 d[DCPIP]= k1[DCPIP] dt where k1 = 1.79 Â± 0.02 dm3 mol-1 s -1 d[DCPIP]= k2 [DCPIP] [N2H4] dt where k2 = 0.13 Â± 0.02 dm3 mol-1 s -1 d[DCPIP]= k2[DCPIP] [H2O2] dt where k2 = 3.01 Â± 0.02 dm3 mol-1 s -1 . The rates of reactions displayed negative salt effect for DCPIP - S2O5 2- reaction, positive salt effect for DCPIP - N2H4 reaction and zero salt effect for DCPIP - SO3 2- and DCPIP - H2O2 reactions. Added cations catalysed the reaction of DCPIP - S2O5 2- but had no significant effect in the reactions of DCPIP - SO3 2- , DCPIP - N2H4 and DCPIP - H2O2. While added anions had negligible effect for all the reactions except DCPIP - N2H4 reaction. There was no evidence of formation of intermediate complex of significant stability for any of the reactions. xvii Free radicals were not detected in all the reactions. Based on the results obtained in these studies, outer-sphere mechanism was proposed for the reactions of DCPIP with S2O5 2- , SO3 2- , H2O2 and inner-sphere mechanism for the reaction of DCPIP with N2H4.