This project was developed because in most laboratories, the main problem is the time a laboratory technician spends finding the best focused image in the microscope. Its objective was to design a program that allows to find the best focused image of a set of images taken from a field of a biological sample using the microscope. To carry out this procedure, the MATLAB software was used, which allows the analysis and processing of digital images. The present work was developed in three stages: Research, development, and simulation, for which the value of the degree of focus and the execution time were considered. In the end, the algorithm that managed to find the focused image and with the fastest execution time was selected.