For several decades, it has been assumed that plasminogen activation may play an important role in tumor invasion and metastasis. The basic idea is that plasminogen activators released from cancer cells catalyze the proteolytic conversion of the inactive zymogen plasminogen to the active proteinase plasmin, which in turn catalyzes degradation of proteins in basement membranes and extracellular matrix (ECM) and thus facilitates cancer cell invasion into the surrounding tissue. Studies have proved that plasminogen activation system also plays a role in processes connected with cancer cell-directed tissue remodelling. Examples of such processes are angiogenesis and desmoplasia, i.e. stimulation of fibroblast proliferation and extracellular matrix protein synthesis. In the text the structures of plasminogen activa- tion system’s elements and theirs role in cancer cells adhesion, migration and invasion based on experi- ments in cell culture model systems are described. Moreover, processes in cancer tumor involving plasmi- nogen activation system and the role of components’ expressions level in prognosis in selected human cancers are discussed.