The free vibration of non-circular cylindrical shells, having a circumferentially varying thickness, is studied in this paper. The variations of curvature and thickness along the circumference are expressed in terms of two independent parameters. Kirchoff-Love assumptions of the classical theory of thin shells are used in arriving at the final equations. The analysis is based on the Ritz method in which a combination of eigenfunctions for beams and quintic Bezier functions are used to represent the displacement fields along the longitudinal and circumferential directions, respectively. The shell model comprises a number of panels in the circumferential direction. The (C^{(0)}, C^{(1)}) and (C^{(2)}) continuities are enforced between the two adjoining panels. Doubly symmetric oval cylinders having constant thickness and second degree thickness variation in each quadrant are investigated in this paper. The results are compared with those which are available from the literature, and were obtained using conventional closed form and finite strip solutions. A study of the changes in mode shapes with the variation of curvature eccentricity and thickness parameters is also presented.