A prospective, controlled, randomised trial was performed to compare the effect of high-energy extracorporeal shock wave therapy (ESWT) versus low-energy ESWT in treatment of rotator cuff tendinopathy. Forty adult patients were included in the study. Patients in the intervention group received 6000 impulses of high-energy (ED+ 0.78 mJ/mm2) in 3 sessions under local anaesthesia. Patients in the control group received 6000 impulses of a low-energy ESWT (ED+ 0.33 mJ/mm2) under local anaesthesia. Follow-up examinations were performed 12 weeks and one year after treatment by an independent observer. An increase in function and a reduction of pain were found in both groups (p < 0.001). Although the improvement in Constant score was greater in the high-energy group compared to the low-energy group, statistical analyses showed no significant difference between the groups with respect to all parameters studied (Constant score/pain/subjective improvement) after 12 weeks and one year follow-up. No statistically significant differences were found between the results of high-energy and low-energy ESWT of rotator cuff tendinopathy.