An ultraviolet cyclonic fluid dosing system for disinfecting fluid materials is described. The dosing system includes a dosing chamber that includes a cylindrical chamber portion and a conical chamber portion. The cylindrical chamber portion has a fluid outlet and a fluid inlet that causes fluid material to enter the upper chamber and travel a helical path down through the upper chamber and into the conical chamber, from where it travels upward in exits through the fluid outlet. As the fluid material passes through the cylindrical and conical chambers, it is dosed with disinfecting ultraviolet light. The system advantageously increases the exposure time of the fluid material to the disinfecting ultraviolet light is increased as compared to non-cyclonic dosing systems having the same volume.