Samah Abd Elazim Ali2022-12-082022-12-082014http://hdl.handle.net/123456789/18253\ i Abstract In this thesis we focused on the concept of Ordinary Differential Equations which appears to be important in physical systems, electri- cal mechanical, Fractional Ordinary Differential Equations and other fields, in particular the basic theory of Fractional Ordinary Differential Equations involving Riernman-Liouville operators and some examples explain their applications. The Laplace transform method has been successfully applied to solve the Ordinary and Fractional Ordinary Differential Equati0ns.The method is very powerful and eflicient in finding solution.la place transformfractional ordianryThesis