In the chapter, the methodological aspects of agile approach to managing the development of startups is described. This approach is an alternative to the traditional waterfall model of project management. Currently, it is associated with two concepts: Customer Development and Lean Startup. It is based on the following assumptions: iterative product creation, learning through feedback from users, admitting the possibility of a radical vision change. The main objective is not to create a perfect product or service, but to learn how to transform an idea for a product or service into a profitable business. The genesis, objectives and methodology of agile development management in startups development, integrating the concept of Customer Development and Lean Startup, are described.