This thesis investigates the selection of project management methodologies in the context of Swiss IT projects, with a specific focus on Agile, Hybrid, and Traditional methodologies. The research is guided by the identification of CSFs and success measures through an extensive analysis of interview and survey data collected from experienced Swiss IT project managers. The dataset consists of nine in-depth interviews with industry experts and a subsequent survey that gathered information from 56 IT projects. The participants in the study represent diverse industries, educational backgrounds, and varying years of project management experience. Through data processing and analysis, key insights and patterns emerge. Agile projects demonstrate a slightly higher average success rate, attributed to their iterative approach and responsive feedback mechanisms. Traditional methodologies excel in cost-effectiveness, emphasizing the importance of rigorous planning and cost control. The dataset reveals that Agile methodologies are typically employed for smaller projects with experienced teams, while Hybrid methodologies are chosen for projects characterized by high uncertainty. Organizational culture and team experience also play significant roles in methodology selection. The findings contribute to the understanding of project management methodologies in IT projects and provide valuable insights for project managers. The research highlights the strengths and weaknesses of Agile, Hybrid, and Traditional methodologies, as well as their alignment with specific project characteristics. This thesis serves as a foundation for future research and offers practical recommendations to enhance project success through informed methodology selection.