OBJECTIVES: Botulinum toxin type A (BoNT-A) is considered one of the treatments of dynamic equinus foot deformity due to spasticity in paediatric cerebral palsy (CP) patients, two years of age or older by decreasing hyperactivity and increasing muscle tone in patients. The aim was to compare the cost of Botox® (Allergan) and Dysport® (Ipsen), considering the administered dose per weight (U/kg) in child patients with equinus foot CP related. METHODS: We performed an observational, longitudinal and retrospective study with data from clinical records from December 1995 to October 2012. Records included patients younger than 18 years old with spasticity treated with BoNT-A at the Pediatric Neurology Service of the Hospital of La Paz (Madrid), with recorded birth and visit dates, weight and dose by muscle. Cost analysis only evaluated four muscle groups (pronator teres, adductor, semitendinosus and triceps surae) including only direct costs (drug and visit costs). We used bootstrap as sensitivity analysis to assess the robustness of results. Costs were in euros 2013. RESULTS: 895 patients treated with BoNT-A for spasticity (543 treated with Botox®, 292 with Dysport® and 60 with both) were included. Baseline characteristics and follow-up were similar in both groups. Patients had an average dose infiltrated per visit of 5.44 U/kg (SD 2.17) for Botox® and 14.73 U/kg (SD 5.26) for Dysport®, and average yearly visits of 3.71 for Botox® and 3.46 for Dysport®. The annual total cost per patient was 850 € for Botox® and 636 € for Dysport®. Of these total costs, annual visit costs of 362 € for Botox® and 347 € for Dysport®, and annual drug costs were 488 € for Botox® and 289 € for Dysport®.  CONCLUSIONS: Based on the real-world management of pediatric spasticity patients with BoNT-A observed in our study, Dysport® could reduce annual total costs per patient.