This research work, aims to study and analyze the quality of illumination, in the internal environment of modern constructions.

Reason interest for dealing with this issue were initially the numerous possi- bilities offered by this, relatively newly established, science of lighting de- sign and the lack of Greek literature that exists for it.

The ultimate purpose of the study is, through the analysis of ideas great professionals of the industry (R. Kelly, W. Lam, J. Flynn, P. Boyce and others) as well as a list of examples, to understand both the importance of, con- troversial, concept of good quality lighting and the methods by which it can be achieved.

The investigation begins with the analysis of qualitative lighting conditions and their categorization into three groups:
• conditions of functionality
• conditions associated with human psychology
• conditions associated with human physiology

After this classification, there are recorded and analyzed two teams of lighting quality criteria. The first includes the figures criteria, which also af- fect the functionality factors and human psychology. Such as the surface level of illumination, uniformity, the brightness distribution, glare, contrasts, color rendering index and color temperature.