Adrenal fatigue is a symptom complex occurring when chronic stress overwhelms one's own adaptation reserve. Morning fatigue, decreased performance, irritability, depressed mood, poor concentration, general myalgia, insomnia, cravings for stimulants, hypoglycemia, postural dizziness are the main symptoms. Adrenal fatigue or exhaustion is not a new concept. Selye presented the concept as a general adaptation syndrome to stress nearly 70 years ago, but it is still a valuable one. It is not easy to measure adrenal function; nowadays salivary cortisol/dehydroepiandrosterone levels taken many times in a day has developed and used frequently. A lot of psychological methods and relaxation techniques including relaxation response, proper nutrition with supplements/herbs, deep sleep and rest, graded exercises and social supports make the patients recover from the state. Diagnostic methods or managements must be developed more to handle this syndrome easily because this syndrome has become much more prevalent than during the last century due to rapid changes and instability of modern societies.