In general, consumers believe that quality of organic food is superior to conventionally produced one. For organic food an integrated assessment of quality seems to be necessary. In the early 20^th century it was observed that living organisms emit light (photons). Different hypotheses were developed to describe this phenomenon. The most prominent one is that the observed biophotons are coming from an intercellular communication system. This effect is meanwhile described as dark luminescence due to the very low intensity of radiation. In first experiments with eggs it was found that eggs from hens of free range systems and from organic production showed higher maximal emissions of biophotons with a slower decline over time. The objective of the present experiment was, therefore, to run a long-term (1 year) evaluation of egg quality from different production systems (cage, barn, free range, organic) on the basis of conventional quality criteria (shell breaking strength, egg mass, albumen height, yolk colour, proportion of yolk, fatty acid profile) and emission of biophotons. First results indicate that organic eggs show higher emissions of biophotons with a slower decline, higher albumen height, paler yolk colour, and higher content of omega-3 fatty acids in yolks. Obviously, measurement of dark luminescence may be a suitable method for an integrated assessment of the quality of organic eggs.