Abstract: Using TEA CO₂ laser as excitation source, we have studied the processes of multiphoton dissociation of propylene oxide (PO), tetrahydrofuran (THF)and diallyl ether (DAE). It was obtained that the dependence of dissociation yield on laser energy-density. We propose a mechanism involving breakage of the C-Obond in PO, THFand DAE. We found that the initiative step of dissociation in these moleculae is breakage of the weaker C-Obond. The threshold energy is about 0.8J/cm².