Technical Abstract: Polymorphism at isozyme loci was used to locate factors responsible for variation in quantitative traits of lentil. 8 sets of random single seed descent (RSSD) derived lines were developed by advancing individual F3 plants of interspecfic (L. culinaris Medik. X L. orientalis Boiss.) hybrids to the F6. The RSSD lines in each of the eight sets differed for alleles at 2-8 isozyme loci. In each set, association of isozyme loci with variation in seven quantitative traits (days to flower, days to mature, plant height, biomass, seed yield, harvest index, seed weight) was determined for each pairwise combination of a quantitative trait with a marker locus. Loci affecting variation in all seven quantitative traits were detected by their association with 14 isozyme markers (Aat-c, Aat-m, Aat-p, Adh-1, Fk, Gal-1, Gal-2, Lap-1, Lap-2, Pgd-p, Pgi, Pgm-c, Pgm-p, Skdh). The known position of 10 of the 14 isozyme loci on the lentil genetic map was used to mark the genomic regions for possible location of associated quantitative trait loci (QTL). Detected QTL were found to be located in six of the seven linkage groups on lentil genetic map. Regions of the genome represented by linkage groups 1, 5, and 7 appeared to affect a greater number of traits than other genomic regions represented by linkage groups 2, 3, and 4. Results indicated that the mean expression of quantitative traits at segregating marker locus classes can be used to locate the genetic factors in lentil which influence the behavior of economically important traits.