AIMS: This post-hoc analysis from the Behavioural Intervention by allied health professionals to promote Physical activity (BIP) trial examined the relationship between depression and step count and walking capacity over two years in people with peripheral artery disease (PAD). METHODS: BIP included participants with walking impairment due to PAD followed up at 4, 12 and 24 months to measure step count over 7 days using an accelerometer and six-minute walking distance. The relationships between depression at entry with step count and walking distance during follow-up were assessed using linear mixed effects models. RESULTS: At entry, 29 (14.5%) of the 200 participants had depression being treated with anti-depressant medication. Participants diagnosed with depression were more likely to be female (13 of 29, 44.8%) than those not diagnosed with depression (43 of 171, 25.1%). Over 24 months follow-up, daily step count progressively decreased in participants with depression (mean [SD] 4406 (2266) at entry to 3888 (2555) at 24 months) as compared to no change in participants without depression (mean (SD) 5271 (2526) at entry compared to 5120 (2446) at 24 months), inter-group difference p = 0.010. No significant difference in change in six-minute walking distance over 2 years was found between participants with and those without depression. CONCLUSION: Depression is associated with greater decline in self-regulated walking in patients with PAD. Effective treatments for depression are needed which help promote physical activity in people with PAD.