The stratospheric concentration profiles of H2 16O and of the isotopic species H2 18O, H2 17O, and HD 16O, are retrieved from far-infrared emission spectra recorded by a balloon-borne Fourier transform spectrometer with 0.0035 cm-1 resolution. The retrievals were carried out using the global-fit procedure on a statistically significant number of transitions for each isotope in the 40--85 cm-1 spectral region. The concentration and the relative mixing ratio distributions of each isotope are given along with the resulting isotopic ratios. A comparison of these results with the natural isotopic abundances shows that there is a depletion of up to 56¿8% of the D- containing isotope of water, while no significant deviation is obtained for the other isotopes within the error bars. A comparison of our results with previously reported measurements is also given. ¿1991 American Geophysical Union