Magnetic resonance imaging is a very significant diagnostic method in modern medicine. It is a necessity in imaging of many pathological conditions of soft tissues and organs. The equipment that is used produces strong magnetic fields, radiofrequency waves and includes magnetic field gradients. This method does not use harmful ionising radiation, but is based on principles of magnetisation and excitation of hydrogen atoms with radiofrequency waves. After the excitation of hydrogen atoms within the human body, relaxation with energy release occurs. The energy is then detected in receiving coils, and electric signal is induced. Produced signal goes through computer processing and is transformed into two-dimensional and three-dimensional images that are used in diagnostics. Observed tissue can be excited in many different ways using sequences. There are two main groups of sequences, those that use spin and those that use magnetic field gradients. By sequencing, different types of images that present tissue in various ways can be obtained. Beside morphology of soft tissues and organs, it is also possible to image their vascularisation as well as the function of any part of the organ, such as stimulated regions of the brain. Magnetic resonance imaging has many advantages because it does not use harmful ionising radiation and it uses gadolinium contrast agents that are rarely associated with side effects. Also, obtained images are very useful in diagnosis of many different conditions. It is very important to be familiar with the limitations that are present in the work with magnetic resonance imaging, so that this method is as safe as possible in everyday diagnostics.