Introduction: Arteriovenous fistula (AVF) is the gold standard for vascular access for hemodialysis in end-stage renal disease (ESRD) patients. There is a high rate of AVF maturation failure, especially in DM patients, and it takes longer for maturation in diabetes mellitus (DM) patients. This study aimed to obtain the recommendations for the minimum diameter of the brachial artery and cephalic vein as a predictor of brachiocephalic AVF maturation in ESRD patients with type 2 diabetes mellitus after six weeks to eight weeks of AVF creation. Methods: This study is a retrospective cohort study using secondary data from patients with brachiocephalic arteriovenous fistula. The examined variables were brachial artery diameter, cephalic vein diameter, and brachiocephalic arteriovenous fistula maturation. Comparative analysis and ROC curve analysis were performed. Results: A total of 72 patients met the inclusion and exclusion criteria. Forty-four (61,11%) patients were mature at six weeks, while 47 (65,28%) were mature at eight weeks postoperatively. At week six, the mature group had a significantly larger cephalic vein diameter (3,20±0,94 vs. 2,65±1,02, p=0,002). At week eight there was a significantly larger brachial artery (4,22±0,70 vs 3,78±0,60, p=0,012), and cephalic vein diameter (3,28±0,98 vs 2,43±0,82, p=0,000) in the mature group. Conclusion: The best threshold value for preoperative brachial artery diameter predicting AVF maturation eighth week was 3.85 mm. The best threshold value for preoperative cephalic vein diameter predicting AVF maturation at the sixth week was 2.45 mm, and at the eighth week, it was 2.45 mm. © 2022, Sanglah General Hospital. All rights reserved.