The use of long, silver nitrate – ethylene glycol gas chromatographic columns has permitted a near base line separation to be achieved for deuterated olefins differing by only one deuterium atom. All of the six deuterated ethylenes and two deuterated butenes have been studied, and good separations have been obtained between the different isotopic species. The isotope effects (KD/KH) on the retention times have been calculated. Evidence of a difference in the relative retention times of two of the ethylene-d2 isomers is presented for the first time. It has been demonstrated that the isotopic content of deuterated olefins can be determined by quantitative analysis with the same accuracy as by mass spectral analysis. A careful study of ethylene-13C failed to reveal an observable isotope effect on its retention time relative to light ethylene.