The master thesis project explores the spare parts business due to the evidence available on how well it contributes to the revenues and profits of firms. With increasing product variety, shorter product lifecycles and market competition, it is necessary for firms to supply spare parts to customers for keeping the products functional. Forecasting for the spare parts aftermarket is difficult due to fluctuating demand rates. These issues make spare parts management challenging. Moreover, the covid-19 pandemic has complicated spare parts management and increased its importance. Therefore, the spare parts business presents opportunities to utilize Additive Manufacturing (AM) technology to solve issues related to spare parts management, which is the focus of this master thesis project. The thesis project has been carried out at Atos SE in the manufacturing consulting domain. Atos aims to identify the technical and economic criteria for selecting spare parts to be produced by AM technology and explore various business models to print and deliver spare parts to customers. The thesis objective has been achieved by conducting a market study on AM technologies & spare parts, and developing a support process using the technical and economic criteria along with the business models. The data and information have been collected using literature study and semi-structured interviews. Through the market study, it was found that Powder Bed Fusion (PBF) is the most industry ready AM technology due to its high processing speed, material compatibility, high strength and mechanical properties and the non - requirement of support structures. The commonly used AM materials are Nylon PA 11 and PA 12, ABS, PLA, Aluminium, Titanium and Stainless Steel. The cost factors driving AM adoption in spare parts were found to be machine, materials, post – processing, labour and energy. The challenges to AM adoption were found to be technology awareness, intellectual property (IP) issues, costs and return on investment (ROI), strength and physical properties of AM produced parts. Following the market study, the criteria identified for selecting spare parts to be AM produced are increased responsiveness, minimized supply disruption, cost optimization, part complexity and sustainability. Furthermore, to select spare parts for AM, multi-criteria decision-making Tools (MCDM) such as AHP (Analytical Hierarchy Process) and PROMETHEE (Preference Ranking Organisation Method for Enrichment Evaluation) have been used and validated. To print the spare parts, four business models have been described in the thesis, using the make-to-stock, make-to-order and engineer-to-order approaches. The study limitations, recommendations, discussions and implications have been enclosed in the master thesis.