The flow of an infinitely conducting inviscid gas in the presence of a magnetic field everywhere parallel to the velocity is considered. Such a flow starting from rest and expanding to supersonic velocities has three transitions, across each of which the flow differential equations change type: from elliptic to hyperbolic, or vice versa. The flow velocities at the three transitions are, respectively, the sound speedc, the Alfve´n‐wave speeda, and the speedca/(c2+a2)1/2. A class of those flows is approximately constructed by solving the flow differential equations, with the flow velocity, etc., prescribed on an axis of symmetry. The solution is in the form of a formal power series in a neighborhood of the axis. The resulting streamlines give possible symmetric nozzle contours. Some mathematical investigations are made to determine the acceptable form of the data to be given on the axis. Numerical examples giving nozzle shapes are included and compared with similar nozzles for nonconducting gases. The procedure described is an extension of that of Friedrichs for ordinary gas nozzles.