The primary aim of this article is to define good lighting for caregivers(both medical staff and families) working in the hospital neonatal intensive care unit (NICU) and other areas associated with the critical care environment. Defining good lighting requires understanding that lighting is not only important for the infants in the NICU but that it also plays significant roles for adults in the NICU. First, lighting supports visual processes (eg, acuity, color vision, visual performance). Second, lighting affects circadian regulation (eg, alertness, sleeping, hormone production). Finally,lighting communicates a message to professional staff as well as parents and visitors about the level of care and sophistication provided by the hospital. By thoughtfully addressing all three roles, the lighted environment in the NICU can support the productivity and well-being of the professional staff, the health and safety of patients, as well as the profitability of the NICU. A secondary aim of this chapter is to provide practical guidance to health care professionals on how to articulate good lighting objectives to application engineers and designers responsible for the lighting in the NICU.