Anxiety was studied on four occasions over one year in 76 men under 66 years of age, who were admitted to hospital with a first acute myocardial infarction. Anxiety was measured by the Spielberger State-Trait Anxiety Inventory, and by a self-rating questionnaire. Average levels of State and self-rated anxiety fluctuated over the study period with levels peaking after admission, falling at the fifth day, rising at six weeks, and falling to their lowest level at one year. Reported specific sources of anxiety, including the myocardial infarction, return to work, the future and possible complications, ranked highest in hospital and at six weeks post-discharge.