Contemporary enterprises can choose one of the two approaches to cope with the increasing changeability of environment. The first, used mostly in big sized enterprises that present high technological and organizational culture, is lean management. By implementing it the enterprise protects itself against the disturbances generated by the environment by elimination and reduction of waists. The second approach is to be agile enterprise what means to be able to identify and use short life time opportunities. One of feature of agile enterprise is its flexibility. Flexibility is meant as the ability of enterprise to extend the repertoire of undertaken opportunities (performed tasks or manufactured products and provided services). In this paper some results of research on flexibility of Polish SMEs are presented. The results include evaluation of both the environment’s changes and how Polish SME’s adopted themselves to the changes. The considered period of the adaptation is 5 years.