Ultrasound examination (US) with a 5 MHz linear array probe was used to examine 30 patients (34 Achilles tendons) with overuse injuries. The results were compared with surgical findings in all cases. Most of the patients had two or more sonographical findings. In this study US had an overall sensitivity of 0.96 in the detection of Achilles tendon pathology. Partial Achilles tendon rupture was suspected in ten tendons. During an operation ruptures were found in eleven tendons, of which two were fibrotic scars. Changes in inflammatory tendopathy (tendinitis, paratenonitis and paratenonitis with tendinosis) were found by US in 28 tendons and in the operation in 27 tendons. US showed tendinitis in 21 cases, of which four had a positive operative finding. In the seventeen negative cases, the surface of the tendon looked normal during the operation. Most of these cases (14 out of 17) were classified as paratenonitis during the operation. In three cases, paratenonitis with tendinosis was classified as paratenonitis in the operation and in one case the findings were similar in US and in surgery. US was underdiagnostic in paratenonitis and overdiagnostic in tendinitis. Bursitis was detected during the operation in ten cases, but only in three cases by US. False positive bursitis was diagnosed three times in US compared to the operative finding. In chronic bursitis, the bursa can be small, thickened by its wall and undetectable by US. High-resolution sonography is a relatively reliable diagnostic method in Achillodynia and mainly useful as a preoperative study to differentiate a partial rupture from inflammatory states.