Measurements of the effects of a weak axial magnetic field on the output energy of a CuCl double‐pulse laser have been made. It was anticipated that the application of a weak 290‐G magnetic field could serve to stabilize the discharge in the laser tube and to, therefore, increase the output energy of the laser. Such increases were observed for large values of the delay time between the two successive electrical discharges but not for the optimum delay of 175 &mgr;sec, and a reduction in the output of the laser occurs for very small time delays. The mechanism by which the magnetic field enhances (or reduces) the laser output is not presently well understood but two alternatives are discussed.