Agriculture is the key development in source of Indian economy. In traditional method there is no provision in identification of disease and it can be visualized only by using naked eye. By keeping this in mind this project mainly focusing in spinach leaves disease detection.Histogram equalization technique is used for adjustment of intensity and contrast of image. Using active contour image segmentation the contour energy is minimized and specifies the curve to detect the object boundaries. The mask argument specifies the initial state of the contour. Morphological operation is performed to remove small protrusions from a segmented image. By using Histogram Oriented Gradients (HOG) feature extraction the disease affected leaves are detected. Then classification is done using ANN and identified as disease and non-disease automatically which requires less computation time and a fine result is produced.