An electronic medication administration record is at the intersection of several disciplines: medicine, nursing, pharmacy, and allied health; however, it is the centerpiece of nurses' work for medication administration in acute care settings. Despite the crucial nature of the electronic medication administration record, human-computer interaction and health literature are silent about design recommendations and evaluations for such records. This study determined critical on-line medication management tasks for acute care nurses through videotaped, semistructured interviews with nurses and then observations of nurses during medication administration tasks. Subsequently, a novel electronic medication administration record prototype was developed and evaluated. The usability evaluation of this new record was positive based upon scores from the Questionnaire for User Interaction Satisfaction and comments about the display. Mean scores for this questionnaire averaged 7.2 to 7.9 (on a scale of 1-9) or from 80.2% to 87.8%. Accuracy scores were low for tasks requiring nurses to examine data outside the immediate field of view. Specific design recommendations are made to alleviate accuracy errors for specific tasks in acute care settings.