ABS TRACT Objective: Patients with solid cancers frequently suffer from thrombosis, which is associated with considerable cost, morbidity, and mortality.The infusional chemotherapy regimen, especially in gastrointestinal cancers, has a long-term need for central venous catheterization.Implantable ports (IP) are increasingly used for the administration of chemotherapy and supportive treatment to cancer patients.Material and Methods: In this study, we evaluated the factors affecting the port thrombosis in gastrointestinal cancers.The patients with gastric, colorectal and pancreatic cancer were included in the study.Results: There were 113 patients with IP locations on subclavian and 7 on femoral veins.IP thromboses were detected in 10 patients.One of the patients had two thrombosis sites on both femoral and subclavian veins.The median time duration from the placement of the port to thrombosis was 4 months.There were 9 patients who underwent treatment with low molecular weight heparin, while one patient received warfarin treatment.There were ten non-port events related to thrombosis events.There was a significant difference between port thrombosis due to location (p<0.0001).This study showed increased thrombotic events in femoral IPs.Pulmonary embolization due to port thrombosis was not observed.Time to thrombose was significantly shorter in femoral IPs (p=0.04).Conclusion: Although femoral IPs have been reported to be safe for the use of breast cancers, great attention must be paid for the utilization of femoral IPs in gastrointestinal cancers.Prospective and larger trials are needed to confirm the results of the present study.