Methyl Parathion (mP) is an organophosphorous pesticide and poses serious threats to the environment including its effect on the humans. The present work deals with degradation of mP using low frequency acoustic cavitational reactors (ultrasonic horn and ultrasonic bath). Effects of presence of TiO2. CCl4 and H2O2 as additives for intensifying the sonodegradation of mP have been investigated. Combination of ultrasound generated cavitation with Fenton type chemistry and photocatalysis has also been investigated to check whether the combination of two techniques with similar mechanisms yield synergistic effects. A mathematical model has also been fitted to estimate the rate constant for pollutant removal under different operating conditions. Additives were found to enhance the sonodegradation of mP significantly due to the generation of additional oxidizing species in the reactor. The present work has clearly illustrated that sonochemical reactors in combination with intensifying agents or combination with other oxidation processes can be effectively applied for the degradation of pesticides. (C) 2011 Elsevier B.V. All rights reserved.