In popular belief urban decay in central Johannesburg drove business northwards into the suburbs and particularly into Sandton Business District, mainly during the late 1980s and 1990s. Evidence collected suggests that active decentralization began much earlier and for a host of reasons. In this respect, the emergence of Sandton Business District fits the pattern associated with poly-nucleate cities globally. Charles Colby’s notion of centrifugal and centripetal forces has been found useful in explaining the changing status of Sandton Business District vis-à-vis downtown Johannesburg, despite the fact that suburbanization was hardly a feature of cities in Colby’s time. It has been found that the emergence of Sandton Business District is explicable in terms of existing academic thinking and literature. The main frameworks employed in the analysis include the shifting dynamics suggested by Colby’s centrifugal and centripetal forces. The importance of an amenity locational orientation, especially with regard to higher-income and mobile communities like those in Sandton; and both the organic and more recently policy-driven push towards the recognition of agglomerative economies in the metropolitan economy, are stressed. The Sandton Business District’s competitive edge was established in the 1970s, with Sandton City providing a high-profile focal point along with then forward-thinking town planning. During the 1980s Sandton Business District emerged as the premier decentralized office address in Johannesburg. The so-called ‘crime and grime’ phenomenon in central Johannesburg only reared up during the 1990s, which is when the major exodus of business commenced and was accelerated by political changes, municipal capacity constraints, and a dearth of applied planning policy. The demand for space in Sandton Business District was exacerbated in the early 1990s when major corporates left the Johannesburg CBD and relocated to Sandton propelled by the escalating centrifugal forces. The reputation of Sandton Business District as the country’s prime financial district was crowned with the relocation of the JSE Securities Exchange to Sandton in 2000. When institutional frameworks and the policy environment for the uni-city of Johannesburg were tightened up in the 2000s, the relationship between Sandton Business District and downtown Johannesburg became clearer. At the same time Sandton Business District was facing severe infrastructural capacity constraints coincidental with a recession in the commercial property market. As the new century progressed, Sandton Business District started to take on the shape of an edge city, something that Garreau (1991) has described as a city on the periphery of an existing, established urban area. The possibility that Sandton Business District has the form of an edge city has also been explored.