International Conference on Numerical Analysis and Applied Mathematics (ICNAAM) -- SEP 19-25, 2011 -- Halkidiki, GREECEWOS: 000302239800383In this paper we propose an exponential fitting (EF) method with two fitting parameters for solving initial value problem x '' = f (x(t), x' (t)) which has oscillatory solutions with varying amplitude. Local truncation error formula is used to determine these fitting parameters. Numerical examples are presented to show efficiency of the method for oscillatory problems in the long time integration.European Soc Computat Methods Sci & Engn (ESCMSE), R M Santilli Fdn, ACC I