Abstract: Objective: To determine the risk factors of thrombosis associated with Peripherally Inserted Central Catheters among cancer patients. Methods: The research was conducted in two tertiary Grade A general hospitals in Guangzhou. It was a retrospective study from January to December, 2014. We recruited the eligible patients and investigated their demographic data, medical history and complications within 3 months of catherization, and then used multiple logistic regression analysis to determine PICC related thrombosis risk factors among cancer patients. Results:Risk factors positively associated with thrombosis were diagnosed cancer for more than seven month, metastases, history of radiation, and fat emulsion/mannitol infusion, and the value of OR and 95% CI were 1.832 (1.092-3.386), 2.358 (1.113-4.996), 4.348 (1.902-9.941), 3.442 (1.044-11.341) respectively. Conclusion: The risk factors of PICC related thrombosis among cancer patients included diagnosed cancer for more than seven month, metastases,history of radiation, fat emulsion/mannitol infusion.