To test the feasibility of a biobehavioral intervention designed to promote physical activity.A randomized, single-blind feasibility trial with a cross-over design.Veterans Administration Medical Center.Military veterans [age: 65.7 (7.8) years; mean (SD)] with non-traumatic lower-limb amputation (LLA), randomized to two groups GROUP1 (n = 16) and GROUP2 (n = 15). Both groups had similar baseline amputation characteristics (level of amputation and time since amputation).Twelve weekly, 30-min telehealth sessions of physical activity behavior-change intervention, with GROUP1 participating in weeks 1-12 and GROUP2 in weeks 13-24. GROUP1 non-contact phase in weeks 13-24 and GROUP2 attention control telehealth phase in weeks 1-12.Feasibility [participant retention, dose goal attainment, intervention acceptability (Intrinsic Motivation Inventory [IMI] Interest and Enjoyment scale), safety] and signal of efficacy [free-living physical activity (accelerometer-based average daily step count), Late Life Function and Disability Index - Disability Scale (LLFDI-DS)].Participant retention rate was high (90%), with 3 participants lost to follow-up during the intervention period. Dose goal attainment was low, with only 10% of participants achieved an a-priori walking dose goal. Intervention was rated as acceptable, with mean IMI Interest and Enjoyment score (5.8) statistically higher than the null value of 5.0 (P = 0.002). There were no between-group differences in adverse event rates (falls: P = 0.19, lower extremity wounds: P = 0.60). There was no signal of efficacy for change in average daily step count (d = -0.15) or LLFDI-DS (d = -0.22 and 0.17 for frequency and limitations scales, respectively).Telehealth delivered biobehavioral intervention resulted in acceptable participant retention, low dose goal attainment, high participant acceptability, and low safety risk, while having no signal of efficacy (physical activity, disability) for people with non-traumatic LLA. This article is protected by copyright. All rights reserved.