Background Tissue factor (TF) is overexpressed in many malignant tumours and is linked to the pathogenesis and prognosis of such malignancies. In vitro studies have proved that reduced expression of TF has inhibitory effect on the angiogenesis and cell proliferation of the malignant tumour. Therefore, TF suppression has been raised as a possible treatment for malignant tumours. Here we investigated the effect of celecoxib on TF expression induced by tumour necrosis factor a (TNF alpha) in PANC-1 cells and a possible molecular mechanism underlying the celecoxib effect. Methods Various doses of celecoxib solution were added to standard cell numbers of PANC-1 cells mixed with equal dose of TNFa for 6 hours. The expression of tissue factor was detected quantitatively by Western blot, whilst the activation of nuclear factor kappa B was tested by electromobility shift assay. Results As the doses of celecoxib increased, the tissue factor expression was decreased in PANC-1 cells and so was the activation of nuclear factor kappa B. Conclusions Celecoxib can downregulate the expression of tissue factor induced by TNFa in PANC-1 cells. This antitumour effect of celecoxib can be explained indirectly via its suppressive role in activation of nuclear factor kappa B.