The egg can be considered as a primary “capsule of life”, in which all ingredients are included in precise amounts necessary to sustain the development of an embryo and give rise to birth of a healthy chick. Thus, the chicken eggshell (CE) contains ions and compounds that are necessary to generate new life, serving as a building material of the new organism. Therefore, it is not surprising that CE of the fertilized egg changes its composition during the process of incubation, which in chicken lasts 21 days. Embryonic development in birds is associated with elution and subsequent absorption of some elements from the shell. The changes in elemental composition of the chicken eggshell during the incubation period were studied using the inductively coupled plasma optical emission spectrometry (ICP-OES). The samples of eggshells were collected on the 1st, 14th, 18th and 21st day of incubation. The statistical analysis (ANOVA) revealed significant differences between the concentrations of five studied elements. The levels of barium, phosphorus and strontium were found to increase whereas those of calcium and magnesium - to decrease during the incubation period. The levels of the other studied elements: boron, iron and zinc remained unchanged during that process. The changes in elemental concentrations that occur during the incubation process can be associated with the request of the growing embryo for certain elements and the solubilities of alkaline earth carbonates.