Working conditions in modern times are a key factor related to fatigue, organizational commitment and job satisfaction of employees in pharmaceutical companies. The purpose of this study was to investigate the levels of fatigue, organizational commitment and professional satisfaction of employees in pharmaceutical companies in the area of Athens. The effect of fatigue on the two aforementioned variables (organizational commitment and job satisfaction) was also investigated. The research involved 102 employees of different specialties (medical visitors, administrators, laboratory staff, etc.) with an average age of 43 years. Participants completed the Fatigue Assessment Scale (FAS), the Meyer and Allen Organizational Commitment Questionnaire, and the Employee Satisfaction Inventory (ESI). The results showed that fatigue was statistically significant corelated with the various dimensions of organizational commitment and job satisfaction, while it was also pointed out that it could be considered as their predictors as well. In conclusion, research on organizational commitment and job satisfaction or interventions aimed at enhancing them should take the fatigue factor into highly consideration.