T he increasing number of workers can not be accommodated in formal sector led to the rapid growth of the informal sector. The growth in the number of merchants in the form of street vendors cause the unavailability of locations for those merchants, so that the merchants occupy the site not in accordance with the designation. Then South Jakarta City Government through the Provincial Governor Instruction of Jakarta Special Capital Region Number 36 Year 2006 regarding the relocation of merchants of Ayodia Park and the surrounding areas, relocate the merchants from Ayodia Park to Radio Dalam Market. But in fact, the relocation has not yet proved effective, as indicated by the number of stalls in the Market Radio In not allocated by the merchant. This study aims to identify location factors that influence the development of ornamental fish and flowers merchants business at Radio Dalam Market. The method used is descriptive method by distributing questionnaires to the traders of ornamental fish and flowers, to identify the internal and external key factors in selecting the business location. Internal factors can be seen from the physical condition of the building, the space of the stalls, facilities and infrastructure, and external factors can be scaled from service and accessibility. The results of this study showed that the main factors that influence the development of the ornamental fish and flowers merchants in Radio Dalam Market is an external factor, namely the non-strategic location of the Radio Dalam Market because of the matters of area accessibility by customers, the entrance to the location is too narrow because it is included in roads and no public transport go directly to the Radio Dalam Market.