The effect of egg collection time, genotype and housing system on egg quality characteristics was evaluated in an experiment with egg type hens (ISA Brown, Hisex Brown, Moravia) housed on litter and in conventional cages. The experiment was conducted from 20 to 64 weeks of age. Eggs were collected and recorded 3 times daily. Once every four weeks, two days in row, all eggs laid were used for egg quality analyses. Egg laying time was dependent on genotype. Housing on litter postponed the time of oviposition. Interactions of all factors were significantly determined also in Haugh units. Eggshell strength was significantly affected by housing system, genotype and egg collection time. It was higher in cages than on litter, and lower in the Moravia genotypein comparison with the other two strains.