Viscoclastic behavior of aqueous solutions of a cationic surfactant, cetyltrimethylammonium p-toluene sulfonate (CTApTS), and an organic salt, sodium p-toluene sulfonate (NapTS), was examined at room temperature by changing concentrations of CTApTS (C-D) and NapTS (C-S). CTApTS forms long threadlike micelles in aqueous solution even at low C-D in spite of the absence of additives. Aqueous CTApTS solutions show pronounced viscoelastic behavior, which is perfectly described by Maxwell model type viscoelasticity, keeping a single set of relaxation parameters (G(N) and tau). The magnitude of relaxation strength, G(N), is Proportional to the square of C-D irrespective of the value of C-S. The value of a relaxation time, tau, is independent of C-D, while the value remarkably reduces with increasing concentration (C-S(*)) of excess pTS(-) ions in the bulk aqueous phase. The relationship between tau and C-S(*) for the system is not identical with that for aqueous solutions of cetyltrimethylammonium bromide (CTAB) and NapTS at C-S* < 30 mmol kg(-1). However, the relationships between tau and C-S* for these systems agree well with each other at C-S* greater than or equal to 30 mmol kg(-1). This implies that formed threadlike micelles in both systems have similar structure and the relaxation mechanism is controlled by C-S*, but not influenced by the presence of Br-ions above C-S* = 30 mmol kg(-1) . (C) 2003 Elsevier Science (USA). All rights reserved.