Two patients (two men aged 42 and 55 years old) with chronic lateral epicondyle tendinosis were treated with a new therapy based on color Doppler ultrasound-guided injection of a sclerosing agent, polidocanol. There was a marked reduction in pain during activity (reported on a visual analogue scale [VAS]) and total disappearance and decrease in neovessels in each case, respectively. Case 1 participated in sports and at the last visit was in the readaptation phase, while case 2 returned to work after having previously abandoned it. Sclerosing neovessels appears to be an effective treatment for painful chronic lateral epicondyle tendinosis, suggesting that neovessels play a key role in causing chronic tendon pain.