Oscillations in the bromate-Mn(II)-organic substrate system are studied by following the concentrations of Mn(III) and Br2 spectrophotometrically, apart from monitoring the concentration of Br- by potentiometry. Limit cycles for the Mn(III)-Br2 combination are constructed experimentally and theoretically. The experimental results agree with the theoretical expectations based on a suggested mechanism. © 1980 Indian Academy of Sciences.