Since the Second World War, North American metropolitan areas have experienced several waves of decentralization from the central city towards the suburbs : population, consumer services, manufacturing, and standardized office functions (« back offices »). Recently, several American authors have begun to speak of a « new suburbanization » involving the shift of high order service activities towards « edge cities ». This article examines the extent to which economic activities have undergone a similar decentralization within the Montréal metropolitan region over the period 1981-1991. The study uses Dun & Bradstreet data which, due to a very fine level of spatial disaggregation, permits a detailed analysis of the dynamics of decentralization in the Montréal region. The results indicate that although the City of Montréal, as a whole, is losing ground to the peripheral zones, its central business district remains very strong economically, especially where high order service functions are concerned.