Evolving fuzzy systems change by online updating of their parameters and structure; the number of fuzzy rules changes as long as there is new data. In literature, an evolving fuzzy system is mainly considered to be an unsupervised approach that builds and updates its clusters online as long as new data is available. In our previous works, we introduced a new supervised evolving fuzzy approach for segmenting medical images. In this paper, we demonstrate that this supervised evolving fuzzy approach can classify images. As an example we attempt to classify medical images based on their modalities. A set of features extracted from the image is used to train the fuzzy system with the modality class of the image as the fuzzy output. The proposed algorithm is applied to both ultrasound scans and magnetic reasoning images (MRI). The proposed algorithm is compared with the support vector machines (SVMs) and the K-nearest neighbour algorithm (KNN). The results show that evolving fuzzy systems can compete with well-establish clustering algorithms (and even surpass them) by delivering high classification rates.