Abscess of the psoas muscle is infrequently encountered. An infectious emergency of this type usually presents in a nonspecific manner and thus poses a significant diagnostic challenge to the emergency physician. Diagnosis and specific treatment are often delayed, which can lead to increased mortality. This case report presents a patient with altered mental status and hypotension after a fall, who was initially managed as a trauma victim. Emergency department evaluation initially focused on a traumatic etiology of the above abnormalities. Subsequent assessment determined that the patient's condition was due to an underlying psoas abscess with sepsis. Appropriate anatomy, clinical presentation, and management are discussed in hopes of increasing physician awareness of this uncommon infectious condition.