A detailed description of a smoke generator system for marker nephelometry, laser velocimetry and flow visualisation research in fluid mechanics is presented. In this generator system a low vapour pressure, commercially available oil is vaporised in a preheated chamber and the carrier gas/vapour stream is rapidly cooled to produce an oil condensation smoke with a particle size in the range of 0.2-2.0 mu m. The thermal and process dynamics of the system have sufficiently large time constants to maintain a relatively close control on the smoke concentration from this type of generator process.