The Krikelas model was used as a framework for investigating supplemental-information-seeking behavior of cardiovascular nurses. (Supplemental information is that which is not available from memory and could be made available by computer.) One hundred seventy-five instances of supplemental-information-seeking behavior were collected from 46 cardiovascular nurses in three metropolitan hospitals. Self-report and observation-interview methods were used. Findings indicated that the nurses sought patient-specific data most frequently, followed by institution-specific data and domain knowledge. They needed a surprisingly large portion of the information to track people, equipment, medications, and reports. The findings have implications for nursing information system design.