Background and Objective: There are limited data on the clinical impact of Covid-19 in patients with acute myocardial infarction (AMI). Aim of this work is to assess the impact of Covid-19 infection on mortality in AMI patients admitted during the national outbreak in Italy. Methods: Retrospective nationwide cohort study enrolling consecutive AMI patients admitted between March,11st and May 3rd, 2020 (national outbreak) and the equivalent periods of the previous 5 years in Italy. The main outcomes were 30-day and 6-month all-cause mortality. Results: The actual number of AMI admission during the 2020 outbreak in Italy was significantly reduced as compared to that expected based on the trend of the previous 5 years (STEMI: 4048 vs 5523, p<0.0001; NSTEMI: 4981 vs 8633, p<0.0001). A Covid-19 diagnosis was reported in 4.2% of STEMI and 3.5% of NSTEMI patients. In STEMI patients the 2020 expected rate of 30-day and 6-month mortality was 9.2% and 12.6%, compared to observed rates of 10.8% (p=0.016) and 14.4% (p=0.017), respectively. In NSTEMI patients the 30-day and 6-month expected mortality rates in 2020 were 6.5% and 12.2%, compared to observed rates of 8.3% (p=0.001) and 13.6% (p=0.041), respectively. Excluding patients diagnosed with Covid-19, the mortality rates become consistent with the trend of the previous 5-year for STEMI, but remain higher for NSTEMI. After multivariate adjustment, diagnosis of Covid-19 resulted an independent predictor of both 30-day mortality (OR=4.7, p<0.0001 for STEMI; OR=4.5, p<0.0001 for NSTEMI) and 6-month mortality (OR=3.6, p<0.0001 for STEMI; OR=3.8, p<0.0001 for NSTEMI). Conclusions: During the 2020 national outbreak in Italy, a concomitant diagnosis of Covid-19 was associated with a significantly higher rate of mortality in both STEMI and NSTEMI patients. Excluding patients diagnosed with Covid-19, the mortality rates become consistent with the previous 5-year trend for STEMI, while they remain higher for NSTEMI.