Since 1996, when Korea's retail industry was liberalised, new store formats such as large discount stores, grew, it was widely believed, at the expense of incumbent rivals such as traditional markets and small operators. This paper seeks to empirically test this proposition: an important underpinning to new regulatory control policies. Research involved a spatial analysis of traditional markets (1,456), large discount stores (408), and SSMs (super-supermarkets or hypermarkets (729)) spread throughout the country, in order to examine the scale and scope of the influence of the new retail store formats. The research is supportive of the 'Traditional Commercial Activity Protection Zones', which protect small and medium-sized enterprises (SMEs). From the perspective of traditional markets, it may be necessary for the South Korean government to promote additional, more proactive, support policies for SMEs.