The effects of work environmental noise and perceived stress on early morning free cortisol levels after awakening were investigated in a group of workers. Previous studies revealed that cortisol levels showed a significant increase after awakening, with high intra individual stability.The aim of this study is to evaluate whether Workers exposed to environmental noise and possible psycho-social stressors could be at risk for alterations on plasma cortisol levels compared to a control group in Morning and Evening. Plasma cortisol levels were determined in 100 Construction workers, 100 Teachers and 50 Drivers.The mean cortisol values of different workers were significantly higher when compared with the control of both male and female. The mean cortisol level detected both in morning and evening were very high inWorkers when compared to the Controls. The authors hypothesise an effect on plasma cortisol levels in workers exposed to environmental noise and possible psycho-social stressors.