Contrary to the prevailing attitude that error is a source of blame and punishment, errors can be an opportunity to discover a problem and institute activities to correct the problem to reduce the likelihood of recurrence. Often the source of error may be the system in which it occurred, not the person associated with it. Error in any domain, including healthcare, is difficult to identify and address because persons are reluctant to report errors for fear of self-incrimination. The discipline of human factors addresses issues related to human performance including use error. Human factors analysis provides insight into the etiology of use errors and how they can be reduced. Patient-controlled analgesia (PCA) pumps were developed to allow the patient or care-giver more control over pain relief. The PCA pumps can be programmed to deliver pain medication on a continuous basis, intermittently, or as a bolus. Selected adverse incidents involving PCA pumps that were due to use error and reported to the U.S. Food and Drug Administration are described. Finally, implications of those findings and the potential for reducing use error by applying considerations of the discipline of human factors are discussed.