From the very beginning of the development of composite resin materials in the 1960s, as aesthetic replacement for amalgam restorations, their properties being enhanced constantly. These improvements can be seen in materials´ physical, chemical and mechanical properties but the most important properties are materials resistance to wear and the reduction of the marginal gap due to polymerization shrinkage of composite resin materials. However, recently, the priority has been to find a material which could simplify and speed up the restorative procedure. Therefore, bulk-fill composite resin materials were invented. In comparison to conventional composite resin materials, bulk-fill composite materials are more translucent in order for the polymerization light to penetrate deeper into the material. Bulk-fill materials are classified, according to their viscosity, as high or low viscosity materials. High viscosity materials can be used to restore the entire cavity, including the occlusal surface, and, low viscosity bulk-fill materials are used as dentin replacement materials and should be covered with at least 2 mm of hybrid composite material. Shade selection of bulk-fill composite materials is limited, however, these materials are mostly used in the posterior region so limited option of different shades does not present a problem. Physico-mechanical properties of bulk-fill composite resin materials are similar to those of conventional composite materials but the most important advantage of these materials is saving time to finish the restoration in the posterior region.