Background. Achalasia, a rare esophageal motility disorder that may cause malnutrition during pregnancy, can result in fetal and maternal morbidity and mortality. Many medical treatment regimens are contraindicated or not tolerated during pregnancy, and surgery is generally avoided due to potential risks to the fetus. Case Report. Severe, medically refractory achalasia in a 23-year-old pregnant woman that caused malnutrition was successfully managed by administering a botulinum toxin A injection to the lower esophageal sphincter. The injection was performed at approximately 14 weeks' gestation and the patient reported clinically significant relief from dysphagia. She gained weight and ultimately delivered a healthy baby girl at term, but her symptoms returned a few months postpartum. She underwent a second treatment of botulinum toxin A injection, but it offered only one month of relief. Roughly eight months after delivery, the patient underwent a laparoscopic extended Heller myotomy and Dor fundoplication. The patient resumed a normal diet one week postoperatively, and her baby has had no complications. Conclusion. This is only the second reported case of botulinum toxin A injection being used to treat achalasia in pregnancy. This treatment proved to be a safe temporary alternative without the risks of surgery and anesthesia during pregnancy.