This study provides an evaluation of the effectiveness of methods to increase handwashing (HW) by nurses working in an intensive care unit. After baseline observations, two interventions were implemented in sequence: three series of classes conducted by the infection control nurse (ICN); and feedback to staff about handwashing errors on the previous day. Staff were aware that handwashing was being observed throughout the study. The educational intervention produced an immediate increase in HW that was followed by a decline to baseline rates over four weeks. Feedback produced an improvement to 97% compliance that was sustained until completion of the study. Improvement in HW compliance following specified critical procedures was also observed following interventions.