Diving is a perilous activity. Long exposure to the subaquatic environment results in many troubles to divers. In Korea, the number of divers, especially recreational ones, is soaring up and the incidence of diving related accidents and illnesses is also increasing rapidly. Consequently, diving medicine which approaches underwater medical problems is getting more important to doctors as well as divers. Decompression sickness (DCS) is one of the most typical diseases in diving medicine, and divers who breathe compressed air or mixed gas always have a risk of suffering from it. DCS is caused by bubbles from dissolved inert gas as a result of decompression. The diagnosis of DCS is based completely on clinical manifestations, but it is not easy to make a correct diagnosis due to various symptoms. In general, DCS needs prompt recompression chamber treatment with trained medical and paramedical staff, but few doctors are trained to handle diving related diseases like DCS and most people in Korea are not aware of diving medicine. Additionally, lack of recompression facilities hinders DCS patients from taking treatment timely. To deal with these problems, Korean government as well as doctors needs to show deep concern at this field.