This paper deals with the combined influences of the vibrational parameters chosen as the material types, number of active turns, helix pitch angle, minimum to maximum radii of the cylinder and maximum cylinder to wire diameters on the first six resonance frequencies of unidirectional composite conical helical springs with solid circle section and fixed-fixed ends. The transfer matrix method based on the distributed parameter model is used for the determination of the fundamental natural frequencies. The rotary inertia, the shear and axial deformation effects are taken into account in the solution based on the first-order shear deformation theory. Variation of the natural frequencies with the chosen vibrational parameters is given in non-dimensional graphical forms. Using these charts, a numerical prediction of the first six linear dimensional free vibration frequencies of composite conical springs and their upper and lower limits with respect to the geometrical and material properties of the spring can be made with a good approximation. Copyright (C) 2004 John Wiley Sons, Ltd.