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The carbon dioxide dissociation has been investigated both theoretically and experimentally in nonequilibrium plasma ofthe glow and microwave gas discharges. Vibrational and gas temperature values have been measured for molecules in plasma and the dissociation degree for the isotopes 12C1602 and 13C1602 after the exit of the gas from the reactor core has been also measured. CARS and absorbtion spectroscopy (with help of frequency tunable diode lasers) methods were used for the investigation.It has been established that under the condition of low vibrational excitation C02 molecules dissociate by direct electron collisions which cause transition from the ground electronic state to the excited repulsive electronic state 1B2 or 3B2. This transition requires more than 8eV when performed from the ground vibrational state and noticably less amount of energy when performed from vibrationally excited state, for example 5.5eV for OOi . The mean electron energy for glow discharge in pure C02 is usually about 2. ..3 eV. That is why the excitation of 1B2 and 3B2 states from vibrationally excited states dominates. Relative population of lower vibrational states of 13C 1602 exceed that of 12C1602 due to lower magnitude of vibrational quantum for 13C1602 (for antisimmetrical vibration mode: E1(12C1602)=2349. 14cm and El(13C1602)=2283 .49cm1). Under this process the direct isotope effect was observed -the dissociation degree a (636) for the heavy isotope 13C1602 exceeded the dissociation degree cx,% a(626) for the light isotope 12C1602. For example, it was a(636)/a(626)=1.35 in the glow discharge of pure C02 at the pressure p=7Torr and the current 1=15 mA (Fig. 1).On the other hand, under the condition of high vibrational excitation another dissociation channel dominated. This channel was associated with step-by-step excitation (VV-exchange) of antisimmetrical vibrations up to the dissociation energy Ed(C02)=5.5eV with following nonadiabatic transition to repulsive state ->B.1 This transition is 0-8194-1504-9/94/$6.00