Nuclear magnetic resonance has emerged as a powerful non-invasive imaging technique in the medical field. It uses magnetic fields and radio frequency signals to obtain anatomical information about the human body as cross sectional images in any desired direction and can easily discriminate between healthy and diseased tissue. Nuclear magnetic resonance images are essentially a map of the distribution density of hydrogen nuclei and parameters reflecting their motion, in cellular water and lipids. Physical principles of magnetic resonance imaging system have been simplified for medical students. Basic components of an NMR imaging system are briefly discussed in the text. A brief note on the MRI of bone, fat, fluid and blood has been added. Features of images of organs such as brain spine, liver, breast and heart as viewed by the magnetic resonance are discussed.