Metabolites of some cyanobacteria and actinomycete species such as geosmin and 2-methylisoborneol (MIB) are generally the sources of earthy and musty odor in surface waters. Peroxone process, that is a combination of ozone (O-3) and hydrogen peroxide (H2O2), has the potential to effectively remove these compounds. In this study, the removal of MIB with the peroxone process was investigated at both laboratory- and pilot-scale systems. Different H2O2:O-3 ratios with 2 mg/L O-3 dosage were applied for determining the optimum ratio of H2O2:O-3 for MIB removal. The optimum H2O2:O-3 ratio and contact time in the laboratory system were determined as 0.3 and 5 min, respectively, whereas they were 0.5 and 15 min for the pilot system, respectively. Although the performances of both systems were different at similar operating conditions, MIB removal efficiencies over 80% were achieved at the optimum conditions specific to laboratory and pilot scale.