The aim of our study was to evaluate the efficacy and safety of ESWL using a modified lateral position in obese patients with renal stones. Nineteen obese patients with renal stones were enrolled (group A). The mean stone diameter was 1.3 cm (0.7-1.9 cm). The mean BMI was 35.1 kg/m² (31-41 kg/m²). Patients were placed in the lateral position, with the energy source facing their body posteriorly and the site where the stone was located in direct contact with the water cushion. Success rate (defined as the percentage of patients who were stone-free or with insignificant fragments after 3 months), mean number of ESWL sessions, mean duration of ESWL session and complications were recorded. The results were compared with those of 17 obese patients (Group B) with similar baseline characteristics treated in the standard supine position. All ESWLs were performed using the Dornier lithotripter SII. Both success rate (68.4 vs. 64.7% for groups A and B, respectively) and mean number of sessions (2.2 vs. 2.6) did not differ significantly between the two groups (p = 0.5). Interestingly, the time required to complete ESWL was significantly shorter for group A patients (56 min) compared to group B (73 min) (p = 0.001). No severe complications (including hematoma, pyelonephritis) were recorded. Our data indicate that ESWL in the modified lateral position for renal calculi in obese patients seems to be feasible and safe. In addition, it is faster than in the supine position since it overcomes technical difficulties. Further studies with a large number of patients are required to support our findings.