Thirty-two patients with chronic plantar fasciitis unresponsive to 9 months of conservative treatment were randomized to receive an ultrasound-guided gastrocnemius injection with botulinum toxin or normal saline. The outcomes of interest included pain on a Visual Analog Scale (VAS), the American Orthopaedic Foot and Ankle Society Hindfoot (AOFASh) scale, range of motion and satisfaction outcomes. Patients were followed for up to 12 months post-treatment. Results showed the botulinum group to display significantly favourable VAS pain scores and AOFASh scores at all time-points compared to the placebo group. Patient satisfaction with the treatment and perceived injection success was greater in the botulinum toxin group. Patients in the botulinum group returned to work earlier than the placebo group.