Nowadays and in spite of all the preventive effort made, cardiovascular diseases remain as one of the leading causes of death worldwide. Current treatments decrease the progression of the disease but fail to offer a solution where the contractile function lost due to the injury can be recovered. In response to this, regenerative medicine proposes new approaches and one of this is the use of biomaterials that can mimic the role of the extracellular matrix and provide support for new cells in the affected heart. This study evaluated the repairing effect of collagen type I and MaxGel when injected, alone or combined, into the infarcted heart of Wistar rats. Cardiac function was quantified using the ejection fraction as the main parameter and it was measured in three time points during the study: pre-infarction, post-infarction, and post-treatment. Additionally, histological samples of the hearts were taken for evaluation. The data obtained showed a marked recovery of the cardiac function in the animals were collagen type I was injected with an increase of 8.2% on the mean ejection fraction, suggesting that this biomaterial has the capacity to stop the progressive decline of the cardiac function in an infarcted heart.