The study of nanofluids represents an innovative research area with remarkable development. Properties of ferric magnetic nanofluids, also denoted as ferrofluids, under the influence of an external magnetic field have attracted increasing attention. A set-up for performing rheological and magnetorheological tests of propylene glycol-based hematite (alpha-Fe(2)0(3)) nanofluids is presented. The nanoparticle concentration dependence of the magnetorheological properties of this nanofluid was analysed at 303.15 K, ranging from 0.2 to 6.18 vol%, while external magnetic fields up to 0.7 T were applied. The rheological and magnetorheological experiments were performed using a rotational Physica MCR 101 rheometer, (Anton Paar), which is equipped with a magnetorheological device (MRD 170/1T) to control the magnetic flux density. A detailed study about the thixotropic behaviour of the samples as well as viscosity curves of magnetization and demagnetization responses, an analysis of the fractal dimension of the aggregates and conclusions about the magnetic field effect on the size of formed aggregates as a function of concentration has been developed in this work. Rheological tests show that the nanofluid studied presents non-Newtonian shear thinning, thixotropic and viscoelastic behaviour. Finally, the magnetic saturation of the material has been studied.