The territorial structure and social organization of artificial groups of two subspecies of the midday gerbil (Meriones meridianus nogaiorum, M. m. psammophilus) were studied under semi-natural conditions. No significant differences in the space usage system of the subspecies under comparison were found. The structure of social interactions was found to be identical in females but different in males: M. m. nogaiorum males exhibited dominance hierarchy, whilst a despotic dominance was found in M. m. psammophilus males. M. m. psammophilus females also exhibited dominance hierarchy.