The kinetics of the sonolytic degradation of aqueous solutions of carbon tetrachloride and hexachloroethane (C2Cl6) were investigated at six different frequencies over the range from 20 to 1078 kHz. The rates of degradation of CCl4 and C2Cl6 were shown to increase with increasing frequency with optimal degradation rates at 500 kHz. At 205 kHz, the relative rates of sonolytic degradation of the three chlorinated methanes followed the order of CCl4 > CHCl3 > CH2Cl2. Hexachloroethane, which was formed as the primary intermediate in the degradation of CCl4, was degraded at a rate comparable to that of CCl4 at all six frequencies.