We report on our results of a pilot study in the use of extra-corporeal shock waves in the treatment of chronic calcific tendonitis of the shoulder. Twenty patients were randomised as part of a prospective controlled trial. 45% had subjective improvement with an increase of 11% in their constant score. This has statistical significance when compared with the control group. We found that ESWT is effective however patients found the treatment painful and we did not achieve the levels of success that had previously been reported in European studies.