Experiments are described which demonstrate the stabilizing influence of an axial magnetic field on confined vortex flow of an aqueous electrolytic conductor generated by two-dimensional, tangential wall jets. For example, using a 10 cm dia. x 40 cm long vortex tube having two feed jets and a single exit orifice at the centre of one end, the tangential Reynolds modulus at trnasition to instability was increased from 500 with no magnetic field to 7600 under the influence of a 75 kG field (corresponding to a Hartmann modulus based on tube radius of 172). The experimental magnetic stabilization results for 1, 2 and 4 slit injection are correlated empirically.