There was a mass outbreak of death caused by transport stress and malnutrition in Japanese macaques imported from Japan at a farm stock in Korea, which were diagnosed on the ground of history taking, clinical finding, hematological examination and necropsy. Twenty eight Japanese macaques imported from Japan died suddenly from the 4th day after arrival in a farm. These animals were confined very small cages individually and lose the appetite for 10 days from shipping. Main clinical findings observed from alive Japanese macaques consisted of hypothermia and dehydration. On hematological observation for typical 4 cases showed increased erythrocytes and packed cell volume. On serum biochemical examination for 3 cases showed hypoglycemia, whereas blood urea nitrogen, aspartate aminotransferase and alanine aminotransferase were increased. On necropsy for 3 cases, hemorrhage and congestion were observed on the lung and the walls of stomach and intestine were thinned. Histologically, hemorrhagic pneumonia and enteritis with loss of villi were seen. The death of these animal was caused by poor management during transport, which was resulted in transport stress and malnutrition.