Hypertension is widely known as a significant factor in the development of cardiovascular diseases. However, there is increasing interest in the potential link between low admission systolic blood pressure (SBP) and higher mortality rates. Therefore, this study aimed to investigate the relationship between admission SBP and the probability of one-year mortality in patients with ST-segment elevation myocardial infarction (STEMI). This study, which used data from registries, focused on patients diagnosed with STEMI between July 2018 and December 2019. The patients were divided into three groups based on their admission SBP: normal (< 112 mm Hg), elevated (112-140 mm Hg), and hypertension (≥140 mm Hg), and were followed for one year. The researchers used Cox proportional models to analyze the data, which allowed them to estimate crude and fully adjusted hazard ratios, along with their corresponding 95% confidence intervals (HR, 95% CI). This study, which included 1159 patients with a mean age of 60.71±12.19, 914 (78.86%) were male, and 108 (9.32%) died within one year. Among the patients, 276 had a normal admission SBP, 338 had elevated SBP, and 545 had hypertension. Those with hypertension had a higher-risk profile, including factors such as hyperlipidemia, BMI, LDL levels, anterior myocardial infarction, and a higher prevalence of females. The crude and fully adjusted hazard ratios (HR) for the relationship between elevated admission SBP and mortality were calculated as 0.36 (95% CI: 0.23-0.56) and 0.43 (95% CI: 0.23-0.81), respectively. The study's findings indicate a connection between increased admission SBP and a decreased probability of one-year mortality among patients with STEMI. Unlike the general population, where there is a direct linear correlation between SBP and the risk of future cardiovascular events, this research demonstrates an inverse relationship between SBP and one-year mortality.