Abstarct: In the wind turbines, the design of blades and their rotational speed range is of great importance. The results of vibrational analysis of the blades and understanding their natural bending frequencies are the first steps in determining the rotational speed range of the turbines. These frequencies must be selected in such a way that they do not coincide with the rotor's rotational speed and its harmonics, and they should be sufficiently spaced apart. Otherwise, the wind turbine will be exposed to various vibrational phenomena, particularly resonance and structural fatigue. In this thesis, analytical methods (Ritz finite element method) and modal testing were utilized to extract the primary natural bending frequency of a 1-kilowatt wind turbine blade at various rotational speeds. In the modal testing process, a composite mold (epoxy resin) was created using an already-in the market-existing plastic blade, followed by the fabrication of a composite blade (polyurethane foam). To determine the modulus of elasticity, tensile tests were conducted on a composite laminate sample using a universal testing machine. Ultimately, the comparison of the results obtained from the aforementioned methods confirmed the validity of the experimental results. The findings of this thesis can enhance the knowledge of designing small wind turbines in determining the appropriate rotational speed and operational range for 1-kilowatt wind turbines, as well as the construction of suitable composite blades.