A parkinsonian patient with severe outlet-type constipation was treated with injection of botulinum toxin into the puborectalis muscle. A total of 30 units (Botox) was injected in two sites. Resting anal pressure, maximum voluntary contraction, and pressure on straining were evaluated before treatment and 4, 8, 12, and 16 weeks afterward. Pressure values declined following treatment, the decline of pressure on straining ending by week 12. Proctography performed 8 weeks after treatment showed improvement in the anorectal angle and evacuation of barium paste. The clinical benefit lasted for approximately 12 weeks. The present data show that botulinum toxin is a promising tool for treating outlet-type constipation in Parkinson's disease.