From 1982 to 2002, the Centers for Disease Control and Prevention (CDC) reported 350 E. coli O157:H7 outbreaks in 49 U.S. states, accounting for 8,598 cases, 1,493 hospitalizations, 354 hemolytic uremic syndrome (HUS) cases, and 40 deaths. Foodborne transmission was the most common route (52%), with ground beef and produce being the primary vehicles. Person-to-person, waterborne, and animal contact transmission also occurred. Outbreaks peaked in 2000, with a median size of 8 cases. Most outbreaks occurred between May and November, and 89% were in communities. Ground beef was the most common vehicle, responsible for 41% of foodborne outbreaks, while produce accounted for 21%. Outbreaks involving ground beef were most common in summer months, and were often linked to fast-food restaurants. Produce-associated outbreaks were also common, with 38% of foodborne cases linked to produce. These outbreaks were often due to cross-contamination during food preparation. Waterborne outbreaks were less common but still significant, with contaminated drinking water causing larger outbreaks. Animal contact outbreaks were rare but increasing, with 11 reported cases. Laboratory-related outbreaks were rare, with only one reported in 2002. HUS was the most severe complication, with a rate of 4.1 cases per 100 outbreak-related illnesses. Ground beef-associated outbreaks had the highest HUS rate (5.5), while waterborne outbreaks had the lowest (2.1). Deaths were rare, with 40 total deaths, mostly due to HUS. Outbreak investigations have led to improvements in food safety, including changes in fast-food cooking practices and regulations for meat and produce. Despite these improvements, E. coli O157 remains a significant public health threat, particularly in foodborne outbreaks. Prevention efforts focus on improving food handling, water safety, and hygiene in daycare settings. Continued surveillance and research are needed to reduce the impact of E. coli O157 infections.From 1982 to 2002, the Centers for Disease Control and Prevention (CDC) reported 350 E. coli O157:H7 outbreaks in 49 U.S. states, accounting for 8,598 cases, 1,493 hospitalizations, 354 hemolytic uremic syndrome (HUS) cases, and 40 deaths. Foodborne transmission was the most common route (52%), with ground beef and produce being the primary vehicles. Person-to-person, waterborne, and animal contact transmission also occurred. Outbreaks peaked in 2000, with a median size of 8 cases. Most outbreaks occurred between May and November, and 89% were in communities. Ground beef was the most common vehicle, responsible for 41% of foodborne outbreaks, while produce accounted for 21%. Outbreaks involving ground beef were most common in summer months, and were often linked to fast-food restaurants. Produce-associated outbreaks were also common, with 38% of foodborne cases linked to produce. These outbreaks were often due to cross-contamination during food preparation. Waterborne outbreaks were less common but still significant, with contaminated drinking water causing larger outbreaks. Animal contact outbreaks were rare but increasing, with 11 reported cases. Laboratory-related outbreaks were rare, with only one reported in 2002. HUS was the most severe complication, with a rate of 4.1 cases per 100 outbreak-related illnesses. Ground beef-associated outbreaks had the highest HUS rate (5.5), while waterborne outbreaks had the lowest (2.1). Deaths were rare, with 40 total deaths, mostly due to HUS. Outbreak investigations have led to improvements in food safety, including changes in fast-food cooking practices and regulations for meat and produce. Despite these improvements, E. coli O157 remains a significant public health threat, particularly in foodborne outbreaks. Prevention efforts focus on improving food handling, water safety, and hygiene in daycare settings. Continued surveillance and research are needed to reduce the impact of E. coli O157 infections.