A rapid and simple procedure for the determination of non-stoichiometric oxygen in YBa2Cu3O7-delta (YBCO) superconductors is described based on the relationship between oxygen content and c-axis parameter of the YBCO structure. To test the proposed method the oxygen content of samples sinterised starting from different precursors has been calculated from X-ray powder diffraction analysis and compared with the oxygen content obtained by iodometric titration with satisfactory correspondence. (C) 2004 Elsevier B.V. All rights reserved.