Magnetic resonance imaging is a diagnostic method, which has been developing since the 1970s for the purpose of improved application in the medicine. The MRI system consists of magnetic coil, gradient coil, radio frequency equipment and computer. Other components include radio frequency transmitter, power supply, MRI probe, screen and cooling system. Due to rare contraindications, the MRI is a preferred diagnostic method. This diagnostic method is primarily efficient in discovering certain diseases in the oral cavity due to the ability of distinguishing different structures of tissue. The most frequent oral cavity diseases include various types of cysts and benign and malignant tumors. Magnetic resonance imaging is very efficient for the early detection of congenital anomalies, such as cleft lip and palate, as well as for the detection of traumatic injuries. The manifestation of cysts in oral cavity still hasn’t been clearly explained, thus there are a few theories. Benign tumor is a mass of cells that lack the ability to metastasize, therefore they do not have negative effect on human life. Malignant tumor (cancer) on the other hand, has a negative effect on human life, causes deformation of organs and tissues, whereas cells invade other tissues and metastasize. Oral cavity cancer may appear on tongue, in the bottom of the oral cavity, on the alveolar mucosa and glands. Cleft lip and palate belong to the group of the most commonly inherited anomalies, which makes them easily detected and diagnosed even in the prenatal age. Mechanical traumas in the oral cavity can be caused by different mechanical factors. Diagnosis is successfully set by the magnetic resonance imaging which shows damaged tissue parts.