The rheological behavior of 1-ethyl-3-methylimidazolium tosylate (EMIMTsO) and its dispersions with aligned and nonaligned multiwalled carbon nanotubes (MWCNTs) has been studied. Raman spectroscopy analysis has been carried out to characterize the samples. The effects of concentration, types of carbon nanotubes (CNTs), and temperature on the viscolelastic behavior of EMIMTsO have been evaluated. Regardless of the concentration and type of added CNTs, a non-Newtonian behavior of the fluids has been found under shear stress. The ionic liquid and the EMIMTsO-MWCNTs 1 wt. % dispersion showed a temperature-induced gelation. However, the addition of small concentrations of MWCNTs prevents the formation of gels. (C) 2017 The Society of Rheology.