Bacterial canker disease is one of the most destructive diseases of walnut trees that causes die back and plant decline and also great damages to quality and quantity of fruits. The disease can be observed in two forms, at depth and the surface of the bark which cause by two bacteria, Brenneria nigrifluens and B. rubrifaciens, respectively. The most important way of the pathogen penetration is the wounds in the trunk and branches which are occurred due to human ‎activities or mechanical harvesting equipment. The disease becomes severe with the deep irrigation and when the nutrition is insufficient and ‎temperature and humidity are high.‎ Current paper explains history, importance, symptoms, biology, host range, sampling and isolation method also differential characteristics of bacteria and methods of disease management.