The effects of compressibility on the laminar radial free jet and wall jet in which there is an axially-symmetrical swirling component of velocity are investigated. On the assumption that the viscosity is proportional to the temperature it is shown that a similarity solution for the velocity distribution exists which is related directly to the solution for incompressible flow. For arbitrary Prandtl number exact solutions of the energy equation, for a wide variety of temperature conditions, are obtained; some of these take on a particularly simple form when the Prandtl number is unity. Solutions for the case of purely radial flow are easily deduced from the results given below.