Aim: Arteriovenous fistulas are created to serve as a vascular access in hemodialysis patients. Our study assessed the Doppler ultrasound characteristics of upper limb arteriovenous fistulas. Material and methods: We carried out a cross-sectional, consecutive sampling study at the Yaoundé University Teaching Hospital. We interviewed consenting patients on maintenance dialysis performed for at least one month via an upper limb arteriovenous fistula, which was subsequently scanned. We compared the proportions and means using chi-squared and ANOVA tests, respectively, with a threshold for significance set at a p value ≥0.05. Results: Between 1 July and 31 August 2022, we recruited a total of 41 participants, of whom 56.1% were males. The mean age of the participants was 48.39 years. Radiocephalic (76%) and brachiocephalic (24%) arteriovenous fistulas were the only types present. The mean flow volume in the arteriovenous fistulas was 680.47 (365.98) ml/min, with 34.1% of the fistulas having a low flow volume. Also, 56.1% of the arteriovenous fistulas were stenosed, with the main site of stenosis being the juxta-anastomotic segment of the efferent vein. Aneurysms (53.7%), reverse flow (51.2%), venous luminal flaps (22%), and thrombus (17.1%) were the most common complications identified in the study population, with 78.05% of the arteriovenous fistulas having at least one complication. Factors associated with arteriovenous fistula stenosis included the patient body mass index and the radiocephalic fistula type. Diabetes, aneurysms, and luminal venous flaps were found to be associated with low flow volume. Conclusions: The prevalence of vascular modifications and stenosis within functional arteriovenous fistulas was high.