Background: Myocardial infarction is considered to be the most common symptom of cardiovascular diseases. Regarding the limitation of access to Morphine sulphate as a special drug and complications followed, this study aims to compare the treatment effects of intravenous acetaminophen and morphine sulphate on the reduction of pain in MI patients and to improve the cardiac performance. Methods: The present study is a triple-blind randomized control trial in which 70 patients were divided into two separated groups and the pain was measured using Visual Analogue Scale. All analysis was done using SPSS Software at the significance level of 5 percent. Results: 42 patients were male (60%) of whom 20 were in case group and 22 in control group. There were no significant difference between intervention group and control group in terms of VAS score (p = 0.520). The index change of VAS over the time was statistically significant (p=0.001) in intervention and control groups (intra group change). The results of variance analysis with repeated measurements showed that mean differences of Ejection Fraction over time in both groups of intervention and control was not statistically significant (p=0.28). Conclusion: The findings of this study demonstrate that although Acetaminophen does not have an improved effect on pain control and cardiac performance than Morphine sulphate, it can be still an appropriate alternative for Morphine sulfate due to the lack of destructive effects and its availability.