Functional Popliteal Entrapment Syndrome (FPES) is caused by compression of neurovascular structures in the popliteal fossa by hypertrophic muscles, provoking severe leg pain with exercise. Treatment is limited to myotomy of hypertrophic musculature. 8 FPES patients underwent imaging and exercise studies, before receiving botulinum toxin A injections (BTX-A) into the gastrocnemius and plantaris muscles. 81.3 % of patients reported clinical improvement on follow-up, and pathological ankle-brachial indices were normalized. BTX-A injection may present a new, safe, effective and non-invasive approach to FPES.