Abstract
Software industry has been shifting from traditional, plan-based software development to agile software development. Agile seems able to prescribe on how to develop a working software faster, but is still unable to give answer what product should be developed. This paper aims to investigate why large companies should adopt Lean startup to seek for radical innovation. This understanding could be used as a basis to confront disruptive innovation where the problem and the solution are both unknown. A single case study was conducted in a large software company. Eight practitioners with different roles were interviewed. We identified the characteristics of internal startups and the lessons learned on practising Lean Startup inside the large software company.