Investigation of the effect of oviposition and time of addition of marble was carried out on 360 Shaver layer hens divided into three groups. During six week trial (from age of 72 to 78 weeks) hens were fed standard diet according to recommendations for Shaver genotype where main source of Calcium was limestone. First group of hens was control and they were fed standard mixture, second group of hens received additionally each morning 2g of ground marble distributed over the feed, and third group of hens received 2 g of ground marble twice a day - Ig in the morning (8 a.m) and Ig in the afternoon (1 p.m). At the end of each week period quality of fresh laid eggs was investigated. Following egg quality characteristics were measured: egg mass (g), shell mass (g), shell thickness (um), shell deformation (um), shell breaking force (kg) and Haugh units were calculated. Obtained results have shown that oviposition had no significant effect on investigated traits. Addition of large particles of marble had positive effect on strength of egg shell. Compared to control group, morning addition of 2g of marble per hen or addition of Ig.in the morning and Ig in the afternoon caused statistically highly significant increase of egg shell strength expressed through greater breaking force and lower value of shell deformation as well as higher values of shell mass and thickness. Compared to control and trial group I, quality of egg white expressed through Haugh units was significantly lower in trial group III.