The computed tomography (CT) is an imaging technique that utilizes x-rays, a type of ionizing radiation, to visualize the internal anatomy of patients. It is based on the principle that different tissues attenuate x-rays with varying intensity. The source of radiation travels around the patient together with the detector that collects data on the amount of radiation that passed thorough the patient’s body. The gathered data is then processed by a computer and converted into 2D and 3D images. Degenerative disease of the lumbar spine has become a global health issue. Lower back pain is the second most common reason for the sick leave in the developed countries. The main purpose of this thesis is to present the CT as one of the most useful diagnostic tools in the cases of lumbar degenerative disease. Besides CT, magnetic resonance (MRI) is also used for a similar purpose, but it is important to note that the indications are often different for the two procedures. As CT uses ionizing radiation, it is potentially harmful for the patient. Therefore, some specialists prescribe an MRI out of caution. Oftentimes in those situations the MRI will be inconclusive and a CT will have to be performed anyways. MRIs are more expensive than CTs so some doctors will rather do a CT first, but if the patient’s condition demanded an MRI, the CT will be unnecessary. In the end, not only will the patient have to have an MRI, but he will also have been needlessly exposed to x-rays. Therefore, another aim of this thesis is to define possibilities and indications for lumbar spine CT.