BACKGROUND Power Doppler ultrasonography is widely used to examine neovascularization in midportion Achilles tendinopathy. The reliability of the grading of the degree of neovascularization has not been examined previously. HYPOTHESIS Power Doppler ultrasonography can be performed with a high interobserver reliability to determine the neovascularization score in patients with midportion Achilles tendinopathy. STUDY DESIGN Case control study (diagnosis); Level of evidence, 4. METHODS Thirty-three symptomatic and 17 asymptomatic Achilles tendons from 25 consecutive patients were included for ultrasound examination. Victorian Institute of Sport Assessment-Achilles score was used to assess the severity of the Achilles tendinopathy. Each tendon was scored twice by different radiologists using the modified Ohberg score for neovascularization. RESULTS The intraclass correlation coefficient for interobserver reliability was 0.85. Neovascularization was observed in 70% (23/33) of the symptomatic tendons and in 29% (5/17) of the asymptomatic tendons. The Spearman correlation coefficient between the Victorian Institute of Sport Assessment-Achilles score and the degree of neovascularization was - 0.16 (P = .10). CONCLUSION An excellent interobserver reliability was found for determining the degree of neovascularization on power Doppler ultrasonography examination. Neovessels were present in a majority of symptomatic tendons. The severity of symptoms was not correlated with the neovascularization score. CLINICAL RELEVANCE Power Doppler ultrasonography is widely used to evaluate tendinopathy without knowledge of the difference in observations between several testers. Interobserver reliability of the evaluation of the degree of neovascularization in chronic midportion Achilles tendinopathy is excellent.