This study aims to empirically investigate the relationships that, until now, in a retail context, have been mostly conceptually based, within a `mythological triangle΄, i.e. as the impact of Internal Marketing and Market Orientation on Organisational Performance. After the validation with SEM analysis of all three constructs, findings clearly indicate that Internal Marketing indeed has a positive significant effect both on Market Orientation and on Organisational Performance. Market Orientation has a positive effect on Organisational Performance. The role of marketing as a philosophy and function focusing both internally and externally has begun to mushroom within retailing in Greece – as in supermarket chains with nationwide coverage. Retailers recognise that when operating in fiercely competitive national and global environments, marketing can create sources of competitive advantage and effectiveness, even prior to being in the market place. [ABSTRACT FROM AUTHOR]