This report discusses about the Integration of Merge Sort and Insertion Sort. MergeSort is a divide-and-conquer algorithm. MergeSort first divides the problem into subproblems and continues to divide sub-problems into smaller sub-problems until no more sub-problems can be divided any further. Since our goal is to sort the items in a given list, after dividing the original problem into many small sub-problems, we have to conquer our sub-problems by sorting the items in each problem recursively. When the size of a sub-problem is relatively small, the overheads incurred by invoking many recursive methods render the MergeSort inefficient. Such inefficiency can be alleviated with the assistance of insertion sort, a sorting algorithm that runs efficiently for relatively small input. A small suitable threshold value (S) will be selected for limiting the size of a sub-problem. Whenever the subproblem size reaches the threshold (S), the algorithm will invoke insertion sort instead of proceeding to divide smaller sub-problems.