Low dose radiotherapy with a total dose of 5-6 Gy is a well established method in Germany to achieve complete relief of symptoms in patients with painful calcaneal spur. Most results were obtained so far using orthovoltage units. An unresolved question nowadays is, if the introduction of the linear accelerator is able to improve the results. From 06/1999 to 12/2001 we treated 287 patients with the diagnosis of painful calcaneal plantar spur in a consecutive series. 137 patients were irradiated by using orthovoltage (200 KV), 151 underwent radiation therapy on the linear accelerator (6 MV). Before and after treatment, as well as in the follow-up, pain relief was reported by 274 patients with 311 localisations in a self-evaluation using a Pain-Sum-Score. 9 patients did not reply, therefore 265 patients with 300 heel spurs were evaluable. Time to initial treatment, duration of pain, and pain events were comparable in both groups, just as was the dose delivered by radiotherapy. After radiotherapy, 111 patients (79.3%) were free of pain in the orthovoltage group, and 126 patients (78.8%) in the accelerator group. In both groups, results of radiotherapy were not influenced by age, gender, left or right localisation, the duration of pain or the therapy before radiation treatment. 19 patients (13.6%) in (O), and 22 patients (13.8%) in (L) reported a noticeable improvement of pain quality. 8 patients (5.7%) in the orthovoltage group, and 8 patients (5.0%) in the accelerator group, respectively, did not observe any change of pain intensity. Only 2 patients (1.4%) in (O) and 4 patients (2.5%) in (L) suffered from an increase of pain after completion of treatment (3 series). The results of our study show that pain relief after radiation of calcaneal spur is not influenced by radiation quality (orthovoltage versus accelerator). In both groups, the number of patients cured was comparable. The percentage of patients showing a decrease of pain, and of those without improvement or with increasing pain was nearly identical. Low dose radiotherapy of calcaneal spur is an effective and harmless treatment that should be more often used in daily practice of this benign disease. The usage of linear accelerators for benign disorders like painful calcaneal spur is not necessary, as the same effects can be achieved with orthovoltage radiation. Conventional orthovoltage units are sufficient for this purpose and identical clinical results were shown by our comparative study.