Technical Abstract: Sunflower disease incidence and severity data was collected in a fall, 2002 survey of 477 fields in eight midwestern states (North Dakota, South Dakota, Minnesota, Kansas, Colorado, Nebraska, Missouri and Texas). The survey, coordinated by the National Sunflower Association, utilized 46 teams of trained participants to collect information on yield, cultural practices, insects, weeds and diseases. The disease portion of the survey concentrated on determining the incidence of nine major diseases: Sclerotinia head rot and stalk rot, Phomopsis stem canker, Rhizopus head rot, Verticillium wilt, downy mildew, rust, white rust, and charcoal rot. Foliar diseases were not recorded since most the survey was conducted when plants were at or near physiological maturity. The most prevalent diseases across the eight-state sunflower production area were those caused by Sclerotinia (5.4% of the U.S. crop), Verticillium wilt (5.4%), and Rhizopus head rot (4.3%). In North Dakota, the leading sunflower production state with 54% of the 2002 U.S. sunflower acreage, the major diseases were Sclerotinia head rot (4.7%), Rhizopus head rot (2.8%) and Sclerotinia stalk rot (2.7%), while in South Dakota, with 21% of the 2002 sunflower acreage, the leading diseases were Verticillium wilt (18%), Rhizopus head rot (5.6%) and Sclerotinia head rot (2.4%). The least prevalent diseases across the eight state region were downy mildew, rust (Puccinia) and charcoal rot, with white rust (Albugo) not found in any surveyed field. In many states, low summer rainfall contributed to low disease incidence. The survey also pointed out regional differences in disease incidence, which highlights the need for seed companies to develop hybrids with resistance to specific diseases.