Objective: Arteriovenous grafts (AVGs) are considered to be an alternative procedure when autogenous fistulas are not feasible. This study was conducted to establish a correlation between the inflow artery and outflow vein size and patency of AVGs.Materials and Methods: This was a retrospective descriptive study. Data was collected from patients who had forearm AVG performed at a university hospital from January 1, 2012, to December 31, 2016. Spearman’s rho correlation test was used to identify the correlation between the artery and vein size and patency of AVG.Results: A total of 34 patients were enrolled in this study. Forearm loop configuration was performed in 33 patients (97%), and straight configuration was performed in one patient (3%). The median size of the brachial artery was 3 mm (interquartile range [IQR]: 2, 4) and that of the vein was 3 mm (IQR: 2, 5). The overall primary patency was 74% at six months, 59% at one year, and 32% at two years. The analysis showed that the primary patency increased with the artery size, but there was a reverse correlation between vein sizes.Conclusion: Small inflow arteries may reduce the primary patency, but small veins do not result in a poor primary patency. Our method can be applied to patients with small veins, where it is still possible to perform forearm AVGs.