Non-small cell lung cancer (NSCLC) is derived from epithelial cells and accounts for approximately 80% of all lung cancers. Cytokeratins are specific for epithelial cells and during malignant transformation the cytokeratin profile usually remains constant. Angiogenesis is the formation of new blood vessels out of the existing vascular bed. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are potent circulating angiogenic factors. The aim of the present study was to determine if increased levels of a new cytokeratin assay (MonoTotal, which in comparison with TPAcyk detects not only fragments of cytokeratins 8 and 18 but also of cytokeratin 19) is correlated with circulating angiogenic factors (VEGF and bFGF) and the secondary aim was to investigate if increased levels of these circulating markers are associated with survival. In the present study, a total of 45 NSCLC patients (26 patients stage IIIa and 19 patients stage IIIb) receiving only curatively intended treatment for advanced NSCLC were included. These patients donated a total of 291 serum samples during follow-up which was investigated for the presence of MonoTotal, VEGF and bFGF. MonoTotal was statistically significantly correlated with bFGF (R=0.26, p=0.00049) and VEGF (R=0.26, p=0.00007). From the time of histological diagnosis until time of death, MonoTotal increased by 603 U/l (p<0.0001). VEGF increased by 430 pg/ml (p=0.0004) whereas the corresponding value for bFGF was 5.93 pg/ml (p=0.018). MonoTotal, a newly developed commercial cytokeratin assay, seems to be a potentially very interesting serum marker that, in conjunction with other clinical data, might be used for monitoring of patients with NSCLC.