The allelic constitution of 169Populus deltoidesMarsh, clones, selected in North America, was studied at 8 marker allozyme loci (Aco‐2, Mdh‐2, Pgi‐2, Pgm‐1, Pgm‐3, 6‐Pgd‐2, 6‐Pgd‐4and6‐Pgd‐5) coding for 5 enzyme systems in root tips. The enzymes were assayed by horizontal starch gel electrophoresis. An examination of the allozyme profiles revealed that twenty‐seven of these selections (16%) were misidentified asP. deltoides.Eighteen of the misidentified selections displayed isozyme genotypes and patterns typical ofP. deltoidesxP. higraL. hybrids (P.xcanadenisMoench) and the remaining nine selections typical ofP. deltoidesxP. balsamiferaL. (P.xjackiiSarg.). The results indicated a need for screening North AmericanP. deltoidesselections used for plantation, breeding, and biological studies to assure their accurate species identification. Allozyme markers can be of potential importance in detecting misidentifiedP. deltoidesspecimens and in ascertaining their correct species identity.