According to guidelines, it is safe for low-risk patients with myocardial infarction (MI) to be discharged within 72 h of hospitalization. However, results coming from registries show that the hospital stay is often much longer in a real-life situation. Data on the length of the hospital stay (LOS) of MI patients in Polish centers are lacking. We enrolled 212 consecutive patients with acute MI. Low-risk patients were defined according to PAMI II criteria: age 45%, no persistent ventricular arrhythmia, and no multi-vessel disease (MVD). The median of the hospitalization length was eight days (Q1: 6; Q3: 9). In low-risk patients (25%), the median of LOS was six days (Q1: 5; Q3: 7) (p < 0.001). In a logistic regression analysis patients age, LVEF, ST-segment-elevation MI and the presence of MVD were independent predictors of longer hospitals stay (≥8 days). During follow up, there were no significant differences in the rates of clinical events between patients with shorter (<8 days) and longer (≥8 days) hospitalization. In a real-life situation, the LOS, even in low-risk patients is much longer than recommended in the guidelines.