Polycrystalline Fe100-xPtx thin films at various compositions (x = 15, 24, 46 and 78) were prepared by r.f. magnetron sputtering technique. X-ray diffraction studies on annealed Fe54Pt46 thin films at 600degreesC revealed an ordered L1(0) gamma(2)-FePt with fct structure. Differential scanning calorimetric (DSC) studies reveal exothermic peaks for phase transformation in different alloy compositions. The activation energies estimated from DSC studies are found to increase with platinum concentration in the films. Scanning electron microscope studies reveal a smooth surface with grain sizes in the range between 50 and 90 nm. The effect of platinum concentration and annealing on the magnetic properties of FePt alloy films are studied. Argon quenched films are found to exhibit better performance and higher values of Ms than rapid thermal annealed films. The energy product (BH)(max) is estimated to be 13 MGOe and the results are discussed.