Electronic Journal of Differential Equations, Vol. 2003(2003), No. 88, pp. 1-11. Title: Harmonic solutions to perturbations of periodic separated variables ODEs on manifolds Author: Marco Spadini (Univ. di Firenze, Italy) Abstract: We study the set of harmonic solutions to perturbed periodic separated variables ordinary differential equations on manifolds. As an application, a multiplicity result is deduced. Submitted April 17, 2003. Published August 25, 2003. Math Subject Classifications: 34C25, 34C40. Key Words: Ordinary differential equations on manifolds; multiplicity of periodic solutions.