Aims: To evaluate the inßuence of simultaneous local anesthesia (LA) on the clinical outcome after repetitive low-energy extracorporeal shock wave application (ESWT) for chronic plantar fasciitis. Methods: A prospective randomized observer-blinded pilot trial was performed in 48 painful heels (40 patients), having been resistant to various conservative treatment procedures for more than 6 months. 24 heels (20 patients) received 3 applications of 1500 impulses of 0.4 mJ/mm2 without LA (Group I)on 3 consecutive days with a conventional ultrasound-guided orthopaedic shock wave device (Sonocur plus, Siemens AG, Erlangen, Germany). 24 heels (20 patients) received 3 applications of 1500 impulses of 0.04 mJ/mm2 with LA on 3 consecutive days (Group II). Main outcome measure was the number of good or excellent outcomes needing no further therapy at three month follow-up. Secondary outcome measure was pain after weightbearing assessed on a visual analog scale (VAS; range, 0–10). Both groups did not differ signiþcantly before the start of the trial. Results: In Group I 16 of 24 (67%) heels reached a good or excellent result, in Group II 7 of 24 heels (29%) at three-month follow-up (p= 0.0199 for difference between groups; difference= 0.38; 95%CI= 0.09 to 0.66). Pain after weightbearing was 2.2±2.6 on a VAS in Group I, and 3.8±2.5 on a VAS in Group II (p= 0.0318 for difference between groups; mean difference= 0.16; 95%CI= 0.01 to 0.30). Conclusions: The simultaneous use of local anesthesia has a negative inßuence on repetitive low-energy shock wave therapy for chronic plantar fasciitis. Further prospective studies should be performed to evaluate more exactly the extent of this negative inßuence.