Background: Life and quality of life on hemodialysis depends on adequate vascular access. An autogenous arteriovenous fistula (AVF) has the best performance, while the use of a central venous catheter (CVC) may have a negative impact on fistula performance and may be associated with increased systemic inflammation. Our objective is to evaluate the performance of vascular accesses in patients undergoing a chronic hemodialysis program. Methods: This is an observational, cross-sectional, and descriptive study that included patients on chronic hemodialysis for more than 90 days. Patients with an acute systemic inflammatory disease and those with acute cardiovascular illness were excluded. Clinical data, dialysis session parameters, and serum levels of inflammatory markers were evaluated. Results: A total of 91 patients were evaluated, 59 (65%) had an AVF and 32 patients (35%) had a CVC. The adequacy rate was 67%; being 67.8% with AVF and 65.6% with CVC. Among the causes of AVF inadequacy, the ones that presented the highest prevalence ratio (PR) were non-mature AVF (PR: 4.055; 95% CI: 2.017–8.151), pseudoaneurysm (PR: 6.580; 95% CI: 3.723–11.629) and presence of hematoma (PR: 4.360; 95% CI: 2.125–8.946), p < 0.001. Among the catheter group, the causes of inadequacy with the highest PR were the presence of access thrombosis, indicating the use of thrombolytics (PR: 11.103; 95% CI: 4.746–25.977; p < 0.001) and infection (PR: 2.984; 95% CI: 1.293–6.889; p = 0.010). Median primary AVF patency was 72 months compared to 7 months of catheters ( p < 0.001). There was no significant difference in serum inflammatory markers between the two groups. Conclusions: Adequacy rates of vascular accesses did not differ between the groups, but the primary and functional patency of AVF is 10 times higher than that of catheters. Infection in dialysis catheters is associated with worse access performance. There was no association between systemic inflammation and vascular access.