An algorithm is given for deriving the analytical dependence of the smallest natural frequency of oscillations of a plane statically determinate regular truss on the number of panels. The Dunkerley method and its simplified version were used. It is shown that the simplified version gives not only a simpler, but also a more accurate formula. It is assumed that the mass of the truss is concentrated in its nodes, and the number of degrees of freedom of the structure coincides with the number of nodes. For analytical transformations and solving recurrent equations, the Maple computer mathematics system was used. The truss stiffness is calculated using the Maxwell–Mohr formula.