The topic of sustainability is especially important in the building industry, as it uses a large portion of natural resources and energy. That is why, in the past years there have been attempts to meet the requirements of sustainability at the normative level, e.g. by means of prescriptions of certain building products, and through several research projects. Furthermore various systems for assessing the sustainability of planning services and buildings were developed. However, these systems only assess projects starting from the planning stage. Yet, for the development of a sustainable project it is essential that the goals of sustainability are pursued from the very beginning. Hence, this master thesis deals with the main steps of project development of sustainable buildings, which start at the idea stage, lead to the decision stage and end at the awarding stage of planning services for each project. Thereby, it becomes obvious that not only planers but also executors are responsible for reaching optimal results. In addition, the builder-owner bears a special responsibility, since he/she can substantially influence the success of any project by making decisions in its initial phase. That is to say, it is the builder-owner, who appoints the necessary consultants, defines the goals and the corresponding parameters of the construction, equipment, implementation specifications and requirements specifications of sustainability. As far as the awarding of planning services is concerned, this thesis outlines various supply models and the available awarding procedure for intellectual services according to BVergG 2006 and illustrates their pros and cons. The project requirements and criteria for awarding contracts, which should already be considered in the project development and planning phase, are being summarized and explained in a criteria checklist. In addition, the Reismann model, the bonus-malus system for variant decisions, and the fulfillment monitoring are developed as bonus models, which can be used to stipulate and monitor the implementation of sustainable aspects. Eventually, based on the gained insights the classic procedure and the system planning procedure are created as two possible methods for project development of sustainable buildings.