The isotopic compositions have been measured mass spectrometrically for xenon fractions released from the carbonaceous chondrite Murchison in stepwise heating experiments. Variation of the isotopic ratios was found to be relatively small: for example, the 136Xe/132Xe ratio in the 600¿C fraction was 0.328 (the atmospheric ratio is 0.330), and the ratio in the 1500¿C fraction was 0.310 (the Sucor ratio is 0.301), whereas the ratios observed in other temperature fractions had intermediate values. It appears that these variations can best be explained as being due to the fact that reservoirs of two isotopically distinct gases (solar and planetary) exist in the meteorite and that mixtures of these gases in various proportions are being released at different temperatures. The major difference in the isotopic compositions of solar and planetary xenon can be atributed to a mass-dependent fractionation process, but the solar xenon contains excesses of xenon isotopes at mass numbers 128, 130, 131, and 132 that appear to have been produced by neutron capture processes that took place in the sun during its deuterium-burning stage. The solar xenon must have been transported from the sun to the meteorites in the form of solar wind. The relative abundances of the light isotopes of xenon in carbonaceous chondrites are appreciably altered by the cosmic ray ray irradiation process. The decay products of 129I and 244Pu further modify the isotopic compositions of xenon fractions released from the carbonaceous chondrities. According to this interpretation, it is unnecessary to assume the existence of the so-called Renazzo-type fission xenon component (CCF or xenon X) in the carbonaceous chondrites.