Objectives. This study was designed to assess the prevalence and persistence of symptoms of depression and anxiety during the first 12 months following acute myocardial infarction (MI).Design and methods. In a prospective study, 288 MI patients were assessed for symptoms of depression and anxiety using the Beck Depression Inventory (BDI) and the State‐Trait Anxiety Inventory (STAI) in hospital,2‐15 days following MI, and 4 and 12 months subsequently.Results. During hospitalization, 89 (30.9%) and 75 (26.1%) patients registered elevated BDI scores (≥10) and state anxiety scores (≥40), respectively. The 4 and 12 month prevalence rates were 37.7% and 37.2% for depressive symptoms, and 41.8% and 40.0% for anxious symptoms, respectively. Depression and anxiety were highly co‐morbid, with 51% of patients experiencing significant levels of depressive and anxious symptoms at baseline. More than half the patients with complete BDI and state anxiety data experienced either elevated symptoms of anxiety or depression throughout the first year following MI.Conclusions. Symptoms of depression and anxiety are prevalent, persistent problems during the first year following MI. This study highlights the importance of routine psychological assessment for MI patients both in hospital and after