This diploma thesis deals with possibilities of application of basalt fibers in concrete and in cementitious composites. In the theoretical part there is a summary of fibers usually used for fiberconcretes. Manufacturing process of basalt fibers is described, and properties of basalt fibers are summarized. Next part deals with properties of basalt fiber reinforced concrete. Concretely fresh properties, physical-mechanical properties, shrinkage and cracking, microstructure and fire resistance. The last chapter deals with fire resistance of concrete in general. The experimental part of this diploma thesis is divided into two phases. There were two mixes of basalt fiber reinforced concrete made with basalt aggregate and one mix of concrete without basalt fibers in the first phase. Density, consistency by slump and air content were determined as fresh properties. As hardened properties density, compressive strength and flexural strength were determined. There was determined the effect of the temperatures 600 and 800 °C on density, compressive strength and outward of specimens. Also, deformation during the high temperature curing was recorded. In the second phase of the experimental part there were three mixes of cementitious composite made with basalt fibers and one cementitious composite without basalt fibers. Density was determined as a fresh property. Material was monitored during its mixing. As a hardened properties density, flexural strength and compressive strength were determined. There was determined the effect of the temperatures 600 and 800 °C on density, flexural strength, compressive strength and outward of specimens.