Viscosity measurements under Newtonian flow conditions have been made to study the effect of organic additives on the micellar association of 0.2 M cetylpyridinium chloride (CPC) in aqueous medium at 30 degrees C containing different fixed concentrations of potassium salts (mainly KCI). 1-Hexanol (C6OH) and n-heptylamine (C7NH2) were used as the organic additives, and relative viscosity (eta(r)) vs [additive] plots were constructed for various KCl concentrations (0-2 NI). In each case, after reaching a maximum, the eta(r) decreased on further addition of the additive (i.e., a peaked behavior). An interesting phenomenon of progressive shifting of the peak position toward lower [additive] was observed with increase in KCl concentration. This peak shift was found to be dependent on nature of the counterion but almost independent on the co-ion nature. The start of viscosity decrease at lower [additive] may be due to the fact that in the presence of KCl (because of its salting-out nature), the palisade layer gets saturated earlier and the excess content begins to solubilize inside the micellar core-the evidence to this effect is provided by performing identical experiments with n-hexane and n-octane. Availability of the additive in the micellar interior could provided more flexibility as well as swelling (of higher degree of sphericity), which forms the basis of viscosity decrease. For a constant CPC content, a well-defined linear relationship was found to exist between [KCI] and [additive] at the viscosity maximum (eta(r)(max)); these results could be helpful to tune viscosities of surfactant formulations.