OBJECTIVE: To determine the frequency and predictors of compliance with hand hygiene (HH) practice in pediatric intensive care. DESIGN: Observational, prospective cohort study performed from February to April 2000. SETTING: Three intensive care units at a tertiary care children's hospital. PARTICIPANTS: Nurses, physicians, respiratory therapists, and other healthcare workers. METHODS: During 156 30-min daytime observation periods, an unidentified observer monitored 2811 opportunities for HH during patient care and recorded HH compliance. MEASUREMENTS AND MAIN RESULTS: Average HH compliance was 34% (946/2811). It was higher (p < 0.001) among respiratory therapists (68%; 171/251) than physicians (37%; 157/426) or nurses (29%; 587/2031). Contact with body fluid secretions was associated with the highest compliance (77%; 46/60), and contact with wounds (71%; 10/14) or indwelling devices (66%; 110/167) were associated with somewhat lesser compliance. The following were important predictors of compliance (all p < 0.01): being a respiratory therapist (odds ratio [OR], 5.1); working in the neonatal intensive care unit (OR, 1.6); and contact with invasive devices (OR, 2.5), wounds (OR, 6.9), or body fluids (OR, 11.5). Compliance was lowest after interrupted patient-care activities (9%; OR, 0.15). Surprisingly, decreased patient-to-nurse ratio (mean, 1.3 +/- 0.3) or opportunities per hr of care (mean, 37 +/- 7) were not independent predictors of compliance. CONCLUSIONS: Average HH compliance was low, but it increased during high-risk patient-care activities. Intensified efforts are necessary to increase caretakers' compliance and the awareness of the risk of bacterial contamination after interrupted patient-care activities.