Sialorrhea is commonly associated with many neurological and systemic conditions. For children and young adults with cerebral palsy, sialorrhea may cause embarrassment and social isolation. Current medical management used for sialorrhea is unsatisfactory. Preliminary studies in adults with sialorrhea have demonstrated that botulinum toxin A as an effective treatment; however, no studies have defined the optimal dose and the duration of botulinum toxin A's effects on sialorrhea in patients with cerebral palsy. We present four patients with cerebral palsy who received botulinum toxin A treatment for sialorrhea. Under ultrasound guidance, body weight-related dosage of botulinum toxin A was injected bilaterally into the parotid glands. All four patients reported distinct improvement within the first 2 weeks following toxin injection. Duration of the toxin's effect varied from 16 to 20 weeks. There were no therapeutic side effects.