X-ray computed tomography (CT) is one of the most accurate methods used in the analysis of drill cores, providing a non-invasive method of studying rocks and imaging their internal structure. Discussed technique gives the possibility to reproduce the CT image in various directions, without the necessity of mechanical interference in the rock material, resulting in the core destruction. Carbonate rocks are a specific group of rocks, very difficult to interpret due to a high variability of a number of parameters, such as: lithology, mineral composition, biogenic structures content, porosity, permeability, and others. The method of X-ray computed tomography (CT) can be very helpful in the analysis of various carbonate rocks features. Application of the X-ray computed tomography before dividing the core into archive and so-called ‘working’ parts can be very useful for the core documentation and archiving. The tomographic examination, carried out in appropriate time, allows to preserve a complete image of the core. X-ray computed tomography data can be used for various analyses and interpretations, including geophysical logs and borehole imaging. Continuous profiles of some parameters (such as density or porosity) along the studied core intervals also can be calculated from the tomographic image.