Ultraviolet-C (UV-C) technology implementation was associated with a 44% reduction in viral infection incidence among pediatric patients in a long-term care facility (incidence rate ratio, 0.56; 95% confidence interval, 0.37-0.84; P=.003). UV-C was included as an adjunct to standard cleaning protocols over a 12-month period; no other new interventions were introduced during this time. The results suggest that UV-C technology is a potentially important component of eliminating the environment as a source of viral infections.