Symptoms commonly defined as the sick building syndrome were studied in a cross-sectional investigation of 147 office workers in five building areas using a linear-analog self-assessment scale questionnaire to define symptoms at a specific point in time. At the same time, the environment in the breathing zone was characterized by measuring thermal parameters (dry-bulb temperature, relative humidity, air speed, and radiant temperature), volatile organic compounds, respi-rable suspended particulates, noise and light intensity, and carbon dioxide and carbon monoxide levels. Demographic characteristics of the occupants and building characteristics were recorded. Up to 25% of the variance in regression models could be explained for mucous membrane irritation and central nervous system symptoms. These two symptom groups were related to the concentrations of volatile organic compounds, to crowding, to layers of clothing, and to measured levels of lighting intensity. Chest tightness was also related to lighting intensity. Skin complaints were related only to gender. Gender, age, and education failed to demonstrate a consistent relationship with symptom categories. This study suggests that the sick building syndrome may have specific environmental causes, including lighting and volatile organic compounds.