We report the successful growth of high-quality Sr3Fe2O7-x single crystals with volumes of up to 0.3 cm(3) by using the floating zone method. Compositional homogeneity of the crystals was verified by powder X-ray diffraction, optical and electron microscope measurements. The X-ray rocking curves of the Sr3Fe2O7-x single crystal gave a full-width at half-maximum (FWHM) of Bragg reflections of 0.02-0.03degrees. The influence of the growth rate on the crystal size and quality was demonstrated. The effect of oxygen annealing was studied by magnetic susceptibility and Raman light scattering experiments. The Fe(+ 3)/Fe(+ 4) ratio was determined both from the magnetization and thermo-gravimetric data. (C) 2004 Elsevier B.V. All rights reserved.