Background: Even though lipoprotein (a) has been linked to heart disease, no one knows how it affects people who have had primary percutaneous coronary intervention (PCI) after an ST-elevation myocardial infarction (STEMI). Objectives: This research aimed to study the relationship between lipoprotein (a) levels and in-hospital outcomes in people who had an acute STEMI after their first percutaneous coronary intervention (PCI). Methods: In a prospective study, 70 people who were eligible for primary PCI and met the criteria for acute STEMI were enrolled. The COBAS c 501 analyzer was used to measure the levels of lipoprotein (a). Patients were allocated two groups based on their lipoprotein (a) levels. Group I had 49 people with low lipoprotein (a) levels (30 mg/dl), and group II had 21 people with high lipoprotein (a) levels (30 mg/dl). Keeping track of hospital results, especially bad cardiac events that are serious (MACE). Results: High levels of Lp (a) were linked to lower EF (p=0.014) and a higher wall motion score index (p=0.013). People with high Lp (a) levels were more likely to have no reflow during angiography (p=0.007). The same was true for the number of damaged coronary arteries (p=0.007). When Lp levels were high, bad things happened more often in the hospital, like acute heart failure, reinfarction, and death. An Lp (a) cut off value of 24.55 mg/dl was used to predict in-hospital adverse outcomes with a sensitivity of 90.9%, a specificity of 91.7%, and an accuracy of 91.4%. Conclusion: In STEMI, high plasma Lp (a) levels can be used to predict severe adverse cardiac events.