Botulinum toxin A (BTX) injections have been used successfully in the treatment of post-stroke foot spasticity, but the optimal dose-response relationship for selected muscles has yet to be established. The aim of this study was to outline beneficial and unwanted effects of three different doses of BTX in the treatment of spastic foot. In this randomised, double-blind, dose-ranging study, 45 spastic feet were randomly allocated to one of three groups, each of which was treated with a different dosage of BTX. The doses were decided on the basis of suggestions in the literature. Outcome measures (Modified Ashworth Scale, Medical Research Council Scale, gait assessment, presence of Achilles tendon clonus, Visual Analogue Scales for Gait Function and Pain, Adverse Effects scale) were applied at baseline, 4 weeks and 4 months after treatment. All the groups showed significant scales scores improvements after treatment with BTX. Group II (mean BTX total dose: 322 U) and Group III (mean BTX total dose: 540 U) showed a greater and more prolonged response than Group I (mean BTX total dose: 167 U). Group III showed the highest rate of adverse effects 4 weeks post-treatment. BTX injections constitute a useful and safe method of improving post-stroke foot spasticity, associated pain, gait speed and function. In particular, the medium BTX dosages (320 UI spread over 2-5 muscles) were found to be both safe and effective in producing long-lasting improvement of spastic foot dysfunction.