Cauda equina syndrome has been implicated as a potential complication of spinal manipulation. A review of the literature from 1911 to 1989 revealed ten reported cases of cauda equina syndrome in patients undergoing manipulation without anesthesia. This article presents three new cases where a temporal association was found between the onset of cauda equina symptoms and lumbar manipulation. The type of manipulation administered and the relationship between the treatment and symptoms is reviewed. In each of these cases both the chiropractic practitioner and the emergency room physician failed to comprehend the nature of the problem and take appropriate action. As a consequence, the patients went untreated for several days. This may have led to residual symptomatology. It is concluded that patients who present with bowel or bladder disturbances, leg weakness, or rectal and genital sensory changes after manipulation, be recognized as experiencing a cauda equina syndrome.