Abstract
This paper investigates commonalities and differences between Agile and Documentation-driven approaches in managing uncertainty in requirement gathering. The research method is a survey collected interviewing sixteen project managers of Italian software companies, 8 using Agile Methods, and 8 using Documentation-driven methods. The results show that Agile and Document-driven companies consider in a different way the problem of changing requirements and the related uncertainty; thus, they manage differently requirements gathering and the relationship with the customer