Economic pressures on healthcare systems have intensified the necessity of demonstrating the unique contribution of nursing care to patient outcomes. The use of nursing information systems (NIS) has increased completeness of some nursing documentation elements. This study's purpose was to evaluate differences in documentation completeness of nurse assessments of patient outcomes (NASSESS), achievement of patient outcomes (NGOAL), nursing interventions done (NQUAL), and routine assessments before and after implementation of an NIS in a 100-bed urban university hospital in west Tennessee and before and after retraining in NIS use and care planning. NIS implementation did not improve documentation within the first six months. However, retraining and continued NIS use did significantly improve NASSESS, NGOAL, NQUAL, and blood pressure documentation 18 months postimplementation. Nurses must evaluate documentation completeness before and periodically after NIS implementation, using results to improve patient record data validity for patient care decisions, quality improvement, and research.