Rapid diagnosis of acute myocardial infarction is critical for intervention and treatment to decrease morbidity and mortality. For this reasons, this study aimed to design a sensitive biosensor for cardiac troponin I (cTnI) for early prediction and intervention. The sensor was designed from golden plate immobilized with anti- cTnI antibody conjugated with horseradish peroxidase (HRP) enzyme. The rate of degradation of H2O2 is directly related to serum cTnI level. Serum cTnI level was quantified from 3 studied groups including; healthy subjects and patients with ischemic heart (IHD) diseases and myocardial infarction (MI) by ELISA and biosensor techniques to achieve the improved sensitivity of the biosensor. It was found that cTnI levels in healthy subjects ranged from 8-13 ng/dl and in patients with IHD ranged from 20 - 41 ng/dl and MI range from 57- 180 ng/dl. The sensitivity of biosensor was ranged from 85-95% compared with ELISA technique. The developed biosensor is promising in ICU hospitals for early diagnosis and prevent complications of the stroke. It is recommended to apply this biosensor in the large scale of patients with different stages of the cardiac disease.