Department of Chemistry, Kakatiya University, Warangal-506 009 Manuscript received 8 March 1983, revised 18 November 1983, accepted 11 February 1984 The kinetics of oxidation of aliphatic and cyclic ketones by N-bromosaccharin has been investigated in aq. acetic acid medium in the temp. range 10-50°. The reaction is found to be first order both with respect to [ketone] and [hydrogen ion] and independent of [oxidant]. The reaction is of ion-dipole type and it does not initiate polymerisation of added acrylonitrile. Thermodynamic parameters like \(\Delta\) H\(\neq\) ,\(\Delta\)S\(\neq\) and \(\Delta\) G \(\neq\) are evaluated. Linearity of Exner's plot and constancy in\(\Delta\)G\(\neq\) values suggest operation of a similar type of mechanism in all the ketones. A plausible mechanism rationalising the observed kinetic data is proposed. The rate expression derived from the mechanism is of the form rate =k[keton]1[H+]1[NBSac]o. The structural effects are discussed