A calculational thermodynamic investigation of the chemical vapor deposition (CVD) of YBa2Cu3O7−xfrom organometallic precursors has been performed, based on the minimization of the Gibbs energy of the Y‐Ba‐Cu‐C‐O‐H chemical system. Thermodynamic data for the participating compounds were selected after a critical assessment of the available thermochemical information and are self‐consistent with an accepted phase diagram. The results are presented in CVD diagrams which illustrate the influence of the most commonly used operating conditions of temperature, pressure, and initial gas composition on the formation of