In the age of sustainable development classical approaches of marketing are challenged. Sustainability marketing goes beyond conventional marketing thinking. It is about building and maintaining sustainable relationships with customers, the social environments and the natural environment. The managerial approach of sustainability marketing differentiates six steps: analysis of socio-ecological problems; consideration of consumer behaviour; normative sustainability marketing; strategic sustainability marketing; operational sustainability marketing; and transformational sustainability marketing. The mainstreaming of sustainability in the theory and practice of marketing is far from being reality. Here, marketing scholars and practitioners have a crucial role to play in the 21st century.