Abstract The object of hydraulic fracturing is to produce a propped fracture extending from the wellbore. Extensive time and effort are expended in measuring rheological properties of crosslinked fluids (without proppant) under simulated downhole temperature and shear-history conditions. Normally, it is assumed that if a fluid meets certain minimum viscosity conditions, it will transport proppant successfully. Measurements of actual proppant transport under dynamic simulated downhole conditions have been attempted and described, but such measurements have been very cumbersome and require significant equipment and expense to execute. Such measurements are well beyond the scope of routine QA/QC analyses. A proppant viscometer recently constructed can measure fracturing fluids containing propping agents across a wide range of concentrations. The device was designed to work as a conventional Fann Model 50-type viscometer. This unique viscometer has been used to measure typical fracturing fluids containing realistic concentrations of proppants, at temperatures and times up to several hours, representative of actual fracturing treatments. The measurements show regions of elastic transport typical of viscoelastic fracturing fluids where proppant is transported efficiently, usually followed by regions of purely viscous transport where proppant slowly settles. The advantage of the new proppant viscometer is that all components of a fracturing fluid, including proppant, can be tested. Shear-history effects of proppants on frac fluids are usually unknown or ignored, but such effects were observed in this work. Breakers were usually added to the fluids, showing reasonable times when the crosslinked fluid no longer transported proppant efficiently and proppant began to settle. This paper shows how different types of fracturing fluids can support proppant based on their chemical type, i.e. metal and borate crosslinked fluids, linear gel fluids, and surfactant gel fluids. Proppant concentrations are also considered. The physical characteristics of the proppant viscometer are also addressed.