This paper consists of a collection of available information on qualitative relations between indoor air environment and worker productivity. While qualitative information is fairly plentiful, quantitative information is quite limited; and what is there, is highly controversial. Some researchers have published measured improvements in productivity of 2.8% to 9.5% due to improved environmental conditions; others claim productivity increases of up to 15%. On the other hand, many people maintain that the measurable changes in productivity are too small and too random to be caused by the indoor environment. While there is no proof that maximum comfort leads to maximum productivity, an improved environment decreases worker complaints and absenteeism. It appears, however, that other factors such as labor-management relations, interaction between workers, and the physical arrangement of their work spaces are far more important to worker productivity than the indoor air quality (IAQ). It seems that when workers have control over their environment, they tend to be more satisfied. When their environment is improved either through management initiatives or as a result of worker complaints, they take it as an indication that management cares for them, and it increases their job satisfaction, which indirectly may increase their productivity. Most studies show that better lighting increases productivity and that working conditions are generally better when windows are provided. Other indoor environmental factors such as acoustics, thermal and olfactory aspects as well as humidity levels and ventilations rates seem to have correlations to worker performance as measured by factory outputs and industrial accidents, all of which are measures of productivity. Indoor environmental quality (IEQ) is important to the health, comfort, and well being of building occupants. It is believed that poor IAQ is associated with a number of different phenomena, most notably, the Sick Building Syndrome (SBS), Building-related Illness (BRI), and Multiple Chemical Sensitivity (MCS), which, of course, have major effects on productivity. And, since that cost of providing the indoor environment is more than an order of magnitude smaller than the cost of the workers in that place, providing a superior environment may well be the most cost-effective way of increasing worker productivity.