This paper presents indications for investigations and health surveillance in indoor environments. The study of the indoor air quality consists of the following phases: acquisition of the necessary information about the indoor environment; sampling strategy and techniques; qualitative and quantitative analysis of contaminants such as particulate, CO2 and CO, NOx, volatile organic compounds, biological agents. The proposed health surveillance is articulated on four lines: periodical health surveillance, when already performed for other risks (e.g. VDT); specific clinical examinations in occasion of particular events; use of a questionnaire for the evaluation of comfort of the workers; health promotion. A team approach, with cooperation between technical and medical experts, is recommended both for periodical risk assessment and when it is necessary to solve specific indoor problems.