Nowadays, millennials living in megacities are facing numerous issues. Most of them are currently experiencing an unsustainable lifestyle. Since this social group is destined to grow in number in the future years, its living status will strongly affect the development of sustainable cities. High frequency relocation, limited savings and lack of time are some of the Millennials’ main issues. Create appropriate solutions to their problems is therefore crucial for a sustainable development. The project aims to investigate Millennials daily life conditions through a human-needs approach performing and, at the same time analyze the possible business-based services that can help this social group to live more sustainable. This has been done through three needs-based service design methodologies that allowed to identify the reasons behind this social phenomenon: a day in life, questionnaires and phone interviews. Furthermore, a co-creation workshop allowed to investigate possible interactions between businesses realities and millennials. This project results demonstrate that there is a need of Business to Customers services which can contribute at the same time to create a sustainable lifestyle and to reduce the environmental impact of the contemporary consumerism-based society. Finally a concept of a product-based reuse service is for this reason developed considering the role of product life cycle in contemporary sustainable issues. To conclude, the importance of a needs-base approach to generate innovative solutions within the topic of service design is highlighted.