Cardiovascular disease [atherosclerosis and subsequent myocardial infarction (MI)] has been associated with primary hyperparathyroidism. We aimed at studying cardiovascular events before and after surgery and mortality after surgery for primary hyperparathyroidism using a historical follow-up design. A total of 674 patients who underwent surgery at three Danish centers between January 1, 1979 and December 31, 1997 were compared with 2021 age- and gender-matched controls. There was an increased incidence of acute MI up to 10 years prior to surgery [relative risk (RR) 2.5, 95% confidence interval (95% CI) 1.5-4.2] and within the first year following surgery (RR 3.6, 95% CI 1.7-7.6). The risk of MI subsequently declined to a normal level more than 1 year after surgery. Patients with MI prior to diagnosis also had a higher postoperative risk of new infarction than did patients without [odds ratio (OR) 6.0, 95% CI 1.2-30.0]. The risk of hypertension, stroke, congestive heart failure, and diabetes was increased before surgery. More than 1 year after surgery only hypertension and congestive heart failure were more frequent in patients than controls. Preoperative cardiovascular disease was associated with an increased risk of death (RR 1.8, 95% CI 1.1-2.8). Mortality following surgery was higher than in the general population between 1979 and 1990 but not between 1991 and 1997. We concluded that there was an increase in acute MI up to 10 years prior to surgery. The risk of MI decreased to a normal level after surgery, which may be important for preventing cardiovascular disease in patients with primary hyperparathyroidism.