The electrochemical behaviour of ortho, meta, para nitrobenzaldehydes and nitrobenzoic acids under the influence of a magnetic field (B = 0.45 Tesla) was examined using cyclic voltammetry. The electroreduction yield was estimated by the electric charges evolved during each cycle. It was observed that the application of the magnetic field induces an enhancement of the -NO2 group electroreduction. These yields of electroreduction seems to depend on the position of the electron withdrawing group : -CHO and -COOH. Two main influences are outlined : the magnetohydrodynamic effect and the magnitude of the dipole moment of each nitro compound. The case of nitrobenzoic acids appears to be more complicated because the molecular and ionic forms coexist at pH 5.5.