The chemical elements of green turtle (Chelonia mydas) eggshells collected from Samandağ Beach (Turkey) were studied to determine differences between elemental composition and changes in physical characteristics. Eggshells from various developmental stages (n  =  67), from successfully hatched eggs (n  =  25) and infertile eggs (n  =  18) were examined using inductively coupled plasma–atomic emission spectroscopy to determine elemental changes during embryonic development. Through the course of egg development, we found changes in concentration of calcium, copper, potassium, sodium, strontium, and zinc but no changes in magnesium.