The fuzzy front end of product development has been studied extensively in previous research, while the fuzzy front end of manufacturing technology development has been largely neglected despite its importance. Only a few empirical studies that examine the fuzzy front end of manufacturing technology development can be found, which have been primarily carried out in the process industry. Therefore, the overall purpose of this paper is to explore the fuzzy front end of manufacturing technology development. Based on three case studies carried out in the manufacturing industry, the findings of the current research highlight key activities in the fuzzy front end of manufacturing technology development and suggest that the fuzzy front end has four sub-phases with overlapping development activities.