Achalasia is a chronic esophageal motor disorder characterized by failure of the lower esophageal sphincter (LES) to relax during swallowing, aperistalsis of the esophageal body, and, often, an elevated resting LES pressure. Pneumatic dilation and Heller cardiomyotomy have been the time-honored, accepted treatments, but each may carry significant morbidity. Recently, intrasphincteric injection of botulinum toxin has been shown to be an effective treatment for achalasia, probably by reducing the excitatory cholinergic tone of the LES. Subjective and objective improvement have been reported in many patients with few reported adverse reactions. Clinical improvement generally lasts 2-6 months with patients often requiring repeat treatment. Although studies directly comparing botulinum toxin injection with pneumatic dilation and surgical myotomy are needed, botulinum toxin injection has rapidly become another therapeutic option in the treatment of achalasia.