Vascular endothelial growth factor (VEGF) is known to play a key role in tumour angiogenesis. Our preliminary published data suggest that plasma-activated platelets rich (P-APR) rather than other plasma compartments (i.e. plasma, plasma-platelets poor) or serum is the more suitable blood fraction for measuring VEGF in a miscellaneous series of gastrointestinal cancer patients. The aim of this confirmatory study was to assess VEGF in P-APR blood compartments of 30 healthy control subjects (HCS) and a homogeneous series of 62 colorectal cancer patients (CRCP), prospectively collected, to evaluate its possible clinical-biological significance. Samples of plasma (P) in both sodium citrate (SC) and sodium citrate-theophylline-adenosine-dipyridamole (CTAD) were collected from venous blood. After the centrifugation and separation methods VEGF levels were detected by ELISA in P-APR. The best differentiation between HCS and CRCP in VEGF level was seen for P-APRCTAD (median value: 255 pg/ml versus 142 pg/ml; p=0.000 by Mann-Whitney U test). No significant correlation among the P-APR VEGF concentrations and the main clinical pathological features was found. We suggest that P-APRCTAD fraction, obtained according to well standardised conditions, could represent the suitable blood compartment for the assessment of VEGF as marker of malignant intestinal transformation.