Objectives: The aim of the study was to detect if serum procalcitonin could be used as an early diagnostic marker for COVID in asymptomatic patients presenting with ST-segment elevation myocardial infarction and if procalcitonin is related to the extent of myocardial injury after the infarction. Patients and Methods: The study was carried out on 150 patients (age 53.39 ± 13.16) presenting to Ain Shams University Hospitals with ST-segment elevation myocardial infarction (STEMI) and received the standard of care management, which is primary percutaneous coronary intervention (PCI). The patients were assessed regarding the demographic data, presence of any symptoms and signs of infection, risk factors, echocardiography and laboratory measures. COVID PCR and procalcitonin were assessed for all patients. Results: Out of all the asymptomatic patients presenting with STEMI whose COVID PCR turned out to be positive, the procalcitonin was positive 24 and 48 hours post presentation with P value <0.001. There was high statistically significant relation between positive procalcitonin and total leucocytic count (TLC) where there was a drop from a median of 11/mm³ with range (4.5– 19) /mm³ in negative procalcitonin to a median of 3.7 /mm³ with range (1.4–12) /mm³ in procalcitonin positive patients. There was high statistically significant relation between positive procalcitonin and rise of C-reactive protein (CRP) value where there was a rise from CRP median value from 12 mg/dL range (2– 40) mg/dL in negative procalcitonin patients to 47 mg/dL range (14– 163) mg/dL in positive procalcitonin patients. Conclusion: There was a strong relationship between procalcitonin and COVID infection in asymptomatic patients thus procalcitonin can be used as an early diagnostic biomarker for COVID infection in patients presenting with myocardial infarction.