In order to give reasons for further advanced multi-faceted research of geothermal utilization, geothermal energy utilization and its integration in urban planning in the long run in the City of Nis were analysed. Regional aspect of this utilization is considered, which is novelty in the planning of the city. The arguments are supported by expert opinions on geothermal utilization acquired abroad and in Serbia that suggest geothermal use within proposals for an eco-city.