Introduction & Objective: Dialysis vascular access complications are important causes of morbidity in chronic hemodialysis patients. The aim of the present study was a comparison of auxillary loop and atraight grafts patency and its complications for hemodialysis access. Materials & Methods: In this cohort study conducted at Shahid Beheshti Medical University, 58 patients who underwent placement of loop or straight access grafts were included in the study. Demographics, primary and secondary patency rates and complications like thrombosis, infection, bleeding, steal syndrome and other complications were compared in these two groups. The collected data was analyzed by the SPSS statistical software using the chi-square test, t-test, and logistic regression. Results: Thrombosis rates were 51.1% and 53.8% in straight and loop groups respectively (P=0.862), steal syndrome rates were 2.2% and 7.7% in straight and loop groups respectively (P=0.341), psudoanevrism were 11.1% and 23.1% in straight and loop groups respectively (P=0.270), bleeding rates were 4.4% and 0% in straight and loop groups respectively (P=0.439), infection rate were 8.9% and 7.7% in straight and loop groups respectively (P=0.892), and primary patency rate after 1 month were 88.9% and 92.3% respectively (P=0.721), and primary patency rate after 24 month were 31% and 55.5% respectively (P=0.058). Secondary patency rate after 3 month were 75.6% and 92.3% respectively (P=0.189), and secondary patency rate after 24 month were 37.9% and 66.7% respectively (P=0.044). Conclusion: PTFE vascular graft seems to be an appropriate vascular access and is a promising alternative when upper extremity arteriovenous fistulas cannot be constructed. Additionally, there was no significant different between two groups for complications and early patency, but late patency was better in loop group. More study is necessary for final judgment.