This study tested the feasibility and safety of next day hospital discharge after successful primary PCI for uncomplicated STEMI. Twenty-three p-PCI patients (out of 271 consecutive patients) who fulfilled the study inclusion criteria were enrolled in the pilot nonrandomized phase (transfer of patients from the coronary unit to a standard ward within 24 hours after their admission) of the study. The randomized phase of the study screened a total of 1946 consecutive STEMI patients undergoing p-PCI in the two participating centers. Only 56 (ie, 2.9% from all p-PCI) very low risk patients residing less than 20 km from the PCI center were selected. They were randomized 1:2 to either a standard hospital stay (group A, n = 19, age, 58 +/- 8) or first day discharge (group B, n = 37, age, 56 +/- 10; NS). There were no serious complications among 79 study patients within 30 days. The duration of hospital stay was 105 +/- 45 hours (group A) and 29 +/- 3 hours (P < 0.0001) in group B. Ejection fraction after 30 days was 56.8 +/- 6.5% in group A versus 57.3 +/- 7% in group B (NS). A patient comfort questionnaire showed a clear preference of first day discharge in all patients randomized into group B. The results indicate that next day discharge after successful p-PCI is feasible and safe in selected uncomplicated STEMI patients.