Rheological properties of cotton pulp dissolved in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) solutions were characterized using an advanced rheometer. The complex viscosity, dynamic modulus, and shear viscosity at different temperature were studied. In the steady shear measurements, all the solutions show a shear-thinning behavior at high shear rates. The complex viscosity as a function of frequency was fitted by extended Carreau-Yasuda model. In all cotton pulp/[Bmim]Cl solutions, the complex dynamic viscosity (eta*) and steady shear viscosity (eta(a)) followed the Cox-Merz rule only at lower frequency. The effects of tested temperature on viscosity and viscoelastic behavior of the solutions were also investigated. The value of activation energy for the dissolution of cotton pulp in ionic liquids was 65.28 kJ/mol at the concentration of 10 wt% and was comparable with the ones for the dissolution of cellulose in NMMO. POLYM. ENG. SCI., 51: 2381-2386, 2011. (C) 2011 Society of Plastics Engineers