BACKGROUND AND AIMS: Studies on the risk of infectious endocarditis (IE) in patients with adult congenital heart disease (ACHD) compared with the general population are limited. This study aimed to determine the risk of first-time IE in ACHD compared with controls without ACHD and the predictors of IE. METHODS: Swedish national registers were linked to identify all patients with ACHD who were born in 1952-1999 and alive at 18 years of age. Approximately 11 controls from the general population were matched by birth year and sex with each patient with ACHD. The patients and controls were followed from 1970 to 2017 until first diagnosis of IE, death, or end of the study (2017). RESULTS: A total of 36,189 patients with ACHD (51.6 % men) and 403,962 controls were included. During a follow-up of 15.5 years (interquartile range: 6.9-28.5), 706 (2.0 %) patients with ACHD and 147 (0.04 %) controls developed IE. The risk of IE was 54.8 times higher (CI 45.9-65.5) in patients with ACHD than in controls. The highest risk was found in patients with complex heart lesions. In ACHD, valvular surgery (hazard ratio 57.3[CI 44.1-74.6]) and CHD-surgery (121.5[CI 96.2-153.4]) were the most important predictors of IE. Diabetes mellitus and a history of ischemic stroke also predicted IE. CONCLUSIONS: The risk of developing IE was almost 55 times higher in patients with ACHD than in controls. In ACHD-patients, previous CHD-surgery and valvular surgery were the most important predictors of IE.