Technical Abstract: This compendium of diseases, pests and other disorders of hop (Humulus lupulus L.) is designed to be a practical reference for anyone interested in growing hops, whether for commercial production, ornamental or home use. Growers, crop advisors, private consultants, home brewers, students, extension agents, entomologists, and plant pathologists will find this compendium a general reference. It is written for individuals with limited training in entomology, plant pathology, and horticultural science but is intended to have sufficient detail to be useful for individuals with more advanced training or expertise. Each section was written and reviewed by internationally recognized experts on the various subjects. The compendium attempts to be inclusive of all diseases and pests known to occur throughout the world’s hop production regions. The introduction consists of information on the genus Humulus, the unique features of commercial and home hop production, harvest, use and chemistry of hop cones, and characteristics of world cultivars. Diseases caused by bacteria, fungi, nematodes, oomycetes, viroids, viruses, and phytoplasmas are discussed in Part I. Numerous pests are discussed in Part II. Part III addresses post harvest, nutrient, and other disorders. A glossary of terms used in plant pathology, mycology, entomology, and general hop production is also included.