OBJECTIVE: Colorectal cancer (CRC) is associated with high incidence and mortality rates. Carcinoembryonic antigen (CEA), a prognostic biomarker for recurrent CRC following curative resection, suffers from low sensitivity, especially in early-stage screening. Intraplatelet angiogenesis regulators (IPAR), such as vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), have been identified as important regulators of tumor growth in CRC. The aim of this study was to confirm the higher preoperative level of IPAR (VEGF and PDGF) in CRC patients compared to controls and to measure IPAR in CEA-negative CRC patients. METHODS: The data and blood of 30 CRC patients and 30 presumably healthy controls were prospectively analyzed and compared. RESULTS: We confirmed elevated preoperative intraplatelet VEGF and PDGF levels in CRC patients compared to controls. Importantly, IPAR were significantly elevated even in CEA-negative CRC patients. CONCLUSIONS: Elevated preoperative intraplatelet VEGF and PDGF levels in CRC patients suggest new possibilities for postoperative monitoring in CRC patients, especially when CEA is negative.