Aim of the research is to form design indicators to guarantee light comfort in hospital environments for inpatients as well for workers. The research is articulated in different phases: drawing up, elaboration and distribution of a questionnaire to study indoor natural and artificial lighting, and effects on human being; architectural and lighting analyses of the investigated hospitals; elaboration -through graphics- of the questionnaire answers; drawing up of design indications for visual comfort in hospitals. These indications relates natural lighting, artificial lighting, indoor spaces and human being.