Deaths originating from excessive, intense and overworked work were first described in Japan in the late 1970s, so the literature was referred to in Japanese as "karoshi". Such that, people who end up suffering from brain hemorrhage or heart attack are losing their lives in Japan due to long and heavy working conditions. Karoshi is death of worker depending on working for average of 65 hours or more per week for 4 weeks or more, or 60 hours or more per week for 8 weeks for more. Symptoms include extreme fatigue, headache, headache, malaise, flu symptoms, and neck pain. As it is understood from these indications, the existence of karoshi cases is closely related to physical and mental fatigue, working late hours, not enough rest. When karoshi cases were examined, all workers without gender, white / blue collar distinction were found to have similar karoshi risk. Health workers, metal and chemical workers, restaurant-hotel employees, bank-advertising-newspaper-office workers, teachers, truck drivers, call center employees are considered as important risk groups. In Japan, 328 workers died in 2005 due to karoshi. In New York City, the number of compensation cases from karoshi is about 200 to 300 every year. There are over 2,000 cases in South Korea. In Turkey, 48 workers died in 2013, 121 in 2014, 155 in 2014, and 68 workers in the first four months of 2016 lost their lives by having a heart attack or brain hemorrhage. According to this, it is thought that the deaths caused by "possible karoshi" have increased rapidly in the last four years. What to do to prevent karoshi: 1. Reduce working hours and excessive work, 2. Provide adequate medical support and treatment, 3. Promote an active and effective dialogue among workers and to provide an efficient and healthy working environment for the employer.   Keywords: overwork, death, causes