This review article was originally prepared for use as supplemental reading material of “Special Course for Protected Horticulture I” in the Graduate School of Horticulture, Chiba University. The contents, therefore, are directed mainly to graduate students majoring in horticulture-related studies. However, professionals in the fi eld of research and implementation of disease management in protected horticulture might well be interested in some sections. First, the article presents discussion of cultural practices for controlling plant diseases that affect vegetable and ornamental crops grown in protected environments such as greenhouses and plastic tunnels. The major diseases are then described based on pathogen types: fungi, bacteria, and viruses that are common in protected horticulture facilities in Japan. This section specifi cally examines symptoms of host plants, characteristics of pathogens, and control measures that are currently available to prevent each disease from infection and development. Finally, a prospective assessment will also be presented regarding plant disease management in protected horticulture.