The aim was to determine the effect of fybrinolytic therapy by streptokinase on chemotherapy and radiation response in human colon cancer cells. The cells were treated with different concentrations of gemcitabine, cis-platine and streptokinase, at a single use or in combinations. Radiation was tested at a dose 0.5, 5 and 15 Gy in three different schedules. The chemotherapy showed higher cytotoxic effect in combination with streptokinase. On the other hand, the combination of chemotherapy with streptokinase and radiotherapy provide no improvement in sensitivity of cancer cells to treatment. The data suggest that fybrinolytic therapy could influence the effect of chemotherapy.