A Goettfert Rheotester 2000 capillary rheometer was used to measure the shear rate dependence of the viscosity of a range of microstructured fluids. The results were compared to those obtained from a Paar Physica MCR301 rheometer, which used torsional shear flow between parallel plates. One microstructured fluid examined was bread dough made from an Australian hard flour. It was found that the viscosity could be reliably measured using the capillary system up to a share rate of approximately 250s^-1. However, the strain dependence of the shear viscosity, as reported by Phan-Thien et al (Rheol. Acta (1997) 36: 38-48) and observed with the MCR301, could not be observed on the capillary rheometer. The viscosity values obtained from the latter instrument corresponded to samples which had not undergone substantial shearing. Experiments have also been carried out on microstructured polymeric materials, such as polypropylene undergoing crystallization.