In order to detect QTLs affecting egg quality traits, an experimental population was developed from two breeds: Green-legged Partridgenous (GlP), a native Polish breed, and a highly productive Rhode Island Red (RIR) stock. ese breeds differ considerably in egg laying performance–the mean egg weight for GlP hens is 48.9 g and for RIR 59.4 g; during the first 100 days of laying GlP hens lay about 40 eggs while the RIR flock, selected over several generations for high laying performance, 81 eggs. QTL analysis was conducted concerning egg quality traits, based on a population of 519 birds (F2). 23 microsatellite loci on chromosomes 1, 2, 3, 4 and 5 were chosen from the Roslin Institute database on the basis of their utility and location. Within the mapped population a linkage analysis was performed of 23 microsatellite markers. rough a linkage analysis twelve QTLs were identified, affecting 9 egg quality traits: egg weight at week 53 of life, albumen weight at week 53, albumen weight at week 33, yolk weight at week 33, yolk weight at week 53, shell weight at week 53, shell thickness at week 33, shell thickness at week 53, shell colour at week 53.