The article develops and substantiates the directions, factors of development, identifies cost groups and socio-economic efficiency of project activities of enterprises in the fashion business. The project in the fashion business is considered to be a set of interrelated, time-limited actions and activities aimed at developing and promoting a fashion product, taking into account fashion trends with available resources (material, labor, financial, technological). The following directions of project activity of enterprises in fashion business are substantiated: partnership programs (including co-branding); changing traditions in the creation and presentation of fashionable goods in order to attract new generations of consumers through benefits that differ from previous generations; introduction of new technologies that become an important addition to fashion items and accessories - Fashion Tech (or FashTech); greening the activities of fashion businesses. The key factors in the development of project activities of fashion businesses are the following: place in the global production chain of value creation; the degree of concentration of enterprises in industrial clusters; availability of highly qualified specialists in the fashion business; the presence of international brands that influence global fashion trends; rich and unique fashion culture; public policy and legal system that support the development of the fashion industry. Such blocks of project activity costs in fashion business as unique know-how, financial capital, talent (human capital) and management are systematized and characterized. The peculiarities of development and advantages of design projects of fashion products are determined, which include the cult individuality of the brand, the sequence of design, the greatest influence of designers on the final products. It is proved that the development of fashion products as a result of project activities of fashion companies affects the utility curve, and the utility curve of consumers who prefer to consume a lot of fashion products deviates to the right.