Sustainable development is not an easy term to conceptualize, despite its recent popularity, because it has been defined in a variety of different ways. Some fundamental published statements on sustainable development from the Brundtland Report and from Haughton and Hunter's recent book on ‘Sustainable Cities’ are interrelated in the search for a more cohensive and integrated framework of principles that summarize the concept and which can be applied to cities. These principles are used as a background to evaluate the 1995 plans for Sustainable Suburbs in the City of Calgary, a city of over three quarters of a million population. It is shown that Calgary's proposals may have many merits but they will hardly radically change the current low density development or provide much sustainability. This conclusion comes from the fact that many of the fundamental features of sustainability are not incorporated in the recommended set of ideas, which seem more like an environmental update of Garden City and Neighbourhood Unit Design principles.