Symptom prevalences of 2,435 workers within 105 office buildings that were identified in health hazard evaluations (HHE) conducted by the National Institute for Occupational Safety and Health are evaluated. A questionnaire obtained information about symptoms experienced on the day of the survey and 4 weeks prior to the survey; illnesses diagnosed by physicians; and perceived comfort levels for temperature, odors, and humidity. The most common symptoms reported at work were eye strain (45%), unusual fatigue (42%), irritated eyes (42%), and nose or sinus problems (39%). Eye strain, eye irritation and fatigue improved away from work. Women reported twice as many symptoms as men. Nineteen percent of respondents met the requirements for multiple sick building syndrome. For physician diagnosed illnesses, 51% reported sinus infections, and 12% asthma. For comfort levels, 51% perceived insufficient air flow, 9% too much air flow, 35% too hot, 32% too cold, and 10% detected chemical odors. The findings demonstrate that symptoms in indoor, nonindustrial environments are pervasive and consistent with findings from the authors' previous experience. The authors conclude that the large numbers of buildings surveyed and different types of employees make the results useful for comparison of prevalence rates in other studies.