Background: Erythrocyte Sedimentation Rate (ESR) is an easy test used to diagnose and monitor inflammatory and infectious diseases. The aim of this study was the evaluation of the performance of three ESR automated analyzers, VES-MATIC 5, CUBE 30 TOUCH, and MINI-CUBE, involving four Italian polyclinics in Rome, Siena, Como, and Arezzo, as well as inter-site variability assessment to detect possible device-dependent and operator-dependent influences. Methods: Accuracy analysis was carried out by analyzing the same samples with all three instruments and comparing them with the Westergren method. Precision was assessed with quality control material through intra-run and inter-run precision. Repeatability was estimated by reanalyzing fresh blood samples belonging to three ESR ranges (low, intermediate, and high) six times. Results: The results showed a strong correlation (Spearman coefficients R²) between the manual method and VES-MATIC 5 (0.978), CUBE 30 TOUCH (0.981), and MINI-CUBE (0.974). The accuracy of all clinics was excellent, with coefficients of variation (CVs) of less than 10% for all instruments. Repeatability confirmed an excellent level for all ESR ranges, with CVs below 10%. Conclusions: The study proved that all three automated instruments offer optimal performance for accuracy and precision and are suitable for both large and small facilities without influences of the laboratory environment.