Medical images modalities are extensively adapted and used for disease diagnosis. These imaging modalities include computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), and X-ray… etc. The problem associated with medical images is the storage space and bandwidth required for archiving and transmission of this kind of images. Thus image compression is a key factor to reduce the bit rate for transmission or storage while maintaining an acceptable reproduction quality In this paper, an efficient ROI compression approach using hybrid lossy lossless compression technique will be presented. This method is based on applying discreet wavelet transform (DWT) as a lossy method and grayscale matrix (GSM) coding algorithm as lossless method. The results show that the performance of the proposed method is much better than the other existing techniques especially with smaller regions of interest.