The geometrical and mechanical properties and chemical composition of different basalt and glass fibers have been investigated. Tensile tests were performed on short basalt fiber made by melt blowing, glass fiber and three different types of continuous basalt fibers made by spinneret method. The chemical composition was evaluated by plasma atomic emission spectroscopy. The geometrical and mechanical properties of continuous basalt and glass fibers were similar to each other in terms of diameter, tensile strength and modulus. Short basalt fibers had considerably lower average diameter and mechanical performance with relatively high standard deviation. The SiO₂ and Al₂ O₃ content of basalt fibers showed correlation with tensile properties of fibers. Results revealed that continuous basalt fibers were competitive with glass fibers and short basalt fibers were weaker in terms of quality and mechanical properties. It was observed that the joint SiO ₂ and Al₂O₃ content of basalt and glass fibers showed correlation with tensile properties of fibers.