This thesis gives a detailed overview of the design of a small hybrid rocket engine (HRE) that is being built in support of propulsion research activities at Ryerson University, and examines the various research-related issues surrounding the operation and performance of an HRE.The engine design work is undertaken with gaseous oxygen (GOX) as the oxidizer and paraffin and polyethylene as the intended fuels, but the system is readily adaptable to other propellant combinations for future investigations. Particular emphasis was placed on the design and analysis of the GOX injector and the nozzle. The injector orifice design was supported by CFD analysis as well as cold-flow testing. The nozzle was initially designed and fabricated from graphite, but a water-cooled copper design is also considered for those occasions when a fully reusable, non-eroding nozzle is desirable for accurate engine performance measurements. The preliminary nozzle design is supported by a steady-state CFD analysis of the nozzle flows and associated heat fluxes.The overall engine design is further evaluated by examination of internal ballistic simulation results, with respect to such factors as expected performance (chamber pressure, thrust, specific and total impulse) for a given oxidizer mass flow rate and nozzle throat size. The requirements for expected future studies, such as for evaluating engine operation and performance below and above the stoichiometric length of the given engine, have been incorporated where possible into the present design.