A quantum dynamical study of the ArI2 predissociation where both vibrational and electronic processes can take place was performed. A set of 5 coupled diatomics-in-molecules (DIM) electronic potentials was used. Both perpendicular and linear initial ArI2(X) isomers were considered. Only the a′ state had non-negligible effect on photodissociation dynamics for the linear isomer. Decay rates oscillated as a function of the vibrational excitation of I2(B) but the intramolecular vibrational energy was the main source of energy which occurred in vibrational predissociation.