Safety is essential in general. Some data requires security to be protected from unwanted things. One way to improve security is to implement encryption. This encryption method is relatively fast compared to another encryption. The algorithm used to perform this encryption is the Advanced Encryption Standard. This thesis discusses the development of medical image encryption systems. The histogram is used to compare the distribution of values and the number of pixels of the original image with the image after processing, as well as the correlation coefficient to determine the correlation between pixels in the image. From the tests that have been done, the Medical Image Encryption System Using the AES Encryption Method will produce a randomized new image with an average RMS Error of 4388.39 and the average value for the horizontal correlation coefficient of 0.03344, vertical of 0.00742 and diagonal of 0.01110.