Background Pain increases the risk for cardiovascular diseases, including myocardial infarction (MI). However, the impact of pain on mortality after MI has not yet been investigated in large studies with long-term follow-up periods. Thus, we aimed to examine various levels of pain severity 1 year after an MI as a potential risk for all-cause mortality. Methods and Results We collected data from 18 376 patients, aged <75 years, who had a registered MI event during the period from 2004 to 2013 and with measurements of potential cardiovascular risk indicators at hospital discharge from the Swedish quality register SWEDEHEART (Swedish Web System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies). Self-reported levels of experienced pain according to EuroQol-5 dimension instrument were recorded in secondary prevention clinics 1 year after hospital discharge. We collected all-cause mortality data up to 8.5 years (median, 3.4 years) after the 1-year visit. The Cox proportional hazard regression was used to estimate hazard ratio (HR) and 95% CI. Moderate pain and extreme pain were reported by 38.2% and 4.5%, respectively, of included patients. There were 1067 deaths. Adjusted HR was 1.35 (95% CI, 1.18-1.55) and 2.06 (95% CI, 1.63-2.60) for moderate and extreme pain, respectively. Pain was a stronger mortality predictor than smoking. Conclusions Pain 1 year after MI is highly prevalent, and its effect on mortality 1 year after MI was found to be more pronounced than smoking. Clinicians managing patients after MI should recognize the need to consider experienced pain when making prognosis or treatment decisions.