Objective: The study examined whether the addition of a night splint to eccentric exercises is beneficial for functional outcome in chronic mid-portion Achilles tendinopathy. Design: One-year follow-up of a randomised controlled single blinded clinical trial. Setting: Sports medicine department in a general hospital. Patients: 58 patients (70 tendons) were included. Interventions: All patients completed a 12-week heavy load eccentric training programme. One group received a night splint in addition to eccentric exercises. Main outcome measurements: Outcome scores were: Victorian Institute of Sport Assessment-Achilles (VISA-A) score, subjective patient satisfaction and neovascularisation score measured with Power Doppler Ultrasonography. Results: For both groups the VISA-A score increased significantly (from 50 to 76 (P < 0.01) in the eccentric group and from 49 to 78 (P < 0.01) in the night splint group). No significant differences in VISA-A score were found between the groups from baseline to one year (P = 0.32). Presence of neovessels at baseline did not predict change in VISA-A score after one year in the whole group (P = 0.71). Conclusion: Eccentric exercises with or without a night splint improved functional outcome at one-year follow-up. At follow-up there was no significant difference in clinical outcome when a night splint was used in addition to an eccentric exercise program. Between three months and one year follow-up, a continuing increase in VISA-A score was found. Assessment of the neovascularisation score with PDU at baseline has no prognostic value on long-term clinical outcome.