Bacterial diseases present an ongoing challenge to the sustainability of apple production. Fire blight is a serious economic threat to apple production in regions of the world where it occurs, and it it is used as an example to present the key issues and challenges which bacterial diseases raise for apple production. The history of fire blight and its spread around the globe, economic impact, symptoms, disease biology, and management were reviewed in this chapter. A case study is also presented on current efforts to develop apple cultivars which are resistant to fire blight disease. Other apple diseases caused by bacteria, including blister spot, crown gall and hairy root, bacterial blister bark and apple proliferation are also considered.