Ferrofluids are conventionally used in such DC magnetic field applications as rotary and exclusion seals, stepper motor dampers, and heat transfer fluids. Recent research demonstrates ferrofluid use in alternating and rotating magnetic fields for MEMS/NEMS application of microfluidic devices and bio-applications such as targeted drug delivery, enhanced Magnetic Resonance Imaging, and hypothermia. This thesis studies ferrofluid ferrohydrodynamics in uniform and non-uniform rotating magnetic fields through modeling and measurements of ferrofluid torque and spin-up flow profiles. To characterize the water-based and oil-based ferrofluids used in the experiments, measurements were made of the mass density, surface tension, viscosity, magnetization curve, nanoparticle size, and the speed of sound. Initial analysis for planar Couette and Poiseuille flows exploit DC magnetic field effects on flow and spin velocities with zero spin viscosity. Above critical values of magnetic field strength and flow velocity, multiple values of magnetic field, spin velocity, and effective magnetoviscosity result, indicating that zero spin viscosity may be non-physical. Torque and spin-up flow profile measurements show the effect of volume torque density and body force density in uniform and non-uniform rotating magnetic fields.