Kinetics of chromium(VI) oxidation of fluorene (Fl) and its halogenated derivatives, namely, 2,7-dichlorofluorene (Fl-Cl), 2,7-dibromofluorene (Fl-Br) and 2,7-diiodofluorene (Fl-I), in perchlorate solutions was investigated at a constant ionic strength of 2.0 mol dm3 and at 25 oC. The progress of the reactions was followed spectrophotometrically. The reactions showed a first order dependence on [Cr(VI)] and fractionalfirst order dependences with respect to hydrogen ion and fluorene derivatives concentrations. Under comparable experimental conditions, the order of the oxidation rates of the fluorene derivatives was: Fl > Fl-I > Fl-Br > Fl-Cl. The mechanism of the oxidation reactions was suggested and the rate-law expression was derived. Values of the rate constants of the slow step along with the equilibrium constants were calculated.