The short-term results after treatment with sclerosing polidocanol injections have been shown to be good in patients with chronic painful mid-portion Achilles tendinosis. This study aimed to evaluate the longer-term effects on tendon thickness, structure and vascularity, patient satisfaction with treatment, and pain during tendon loading activity. Ultrasonography (US) + colour Doppler (CD) was used for evaluation of the tendon, and the patients graded the amount of pain during tendon loading activity on a VAS. Forty-two patient's tendons (23 men and 19 women, mean age 53 years) with a long duration (mean 32 months) of pain symptoms from mid-portion Achilles tendinosis (US + CD showed a localised thickening, structural changes and neovascularisation), were at three (mean) occasions (6-8 weeks in between) treated with US and CD guided injections of the sclerosing substance polidocanol, targeting the area with neovessels ventral to the tendon. After treatment, 37 patients were satisfied with the results of the treatment and back to previous (before injury) activity level. At the 2-year follow-up (mean 23 months), 38 patients were satisfied with the results of the treatment, and there was a significant reduction in VAS (from 75 to 7; P < 0.05). US showed a significant reduction in the mean mid-portion tendon thickness (from 10 to 8 mm, P < 0.05) and a "more normal" structure. CD showed no, or a few, remaining neovessels in the majority of the successfully treated tendons. In conclusion, treatment with sclerosing polidocanol injections in patients with chronic painful mid-portion Achilles tendinosis showed remaining good clinical results at a 2-year follow-up. Decreased tendon thickness and improved structure after treatment, might indicate a remodelling potential?