We examine the retrievability of stratospheric aerosol size distributions from stratospheric aerosol and gas experiment (SAGE) II extinction measurements. Analytical size distributions, which have been fitted to in situ measurements, are used as a model in conjunction with a Mie scattering code to produce synthetic extinction spectra at the SAGE II observational wavelengths. These synthetic data are analyzed using a constrained linear inversion procedure to deduce the variety of particle size distributions which can satisfy them. Fidelity of the retrieval depends on the range of radii over which the inversion is carried out and the range of wavelengths over which measurements are available, but is less sensitive to the number of wavelength channels. As expected, solutions are not unique and depend upon the weighting function used to constrain the solution and the degree of smoothness imposed. A given set of extinction measurements may be attributed to either a unimodal or bimodal size distribution, and the selection of a single solution is always subjective to some degree. For bimodal distributions the larger particle mode can be recovered reasonably well; however, the smaller particle mode of a bimodal distribution or the single mode of the background aerosol, which lie below the experiment's sensitivity range, cannot be retrieved accurately. The retrieval of any physically reasonable solution becomes increasingly difficult in the presence of experimental error. In many simulations in which a 10% random error was added to the extinction measurements, only solutions which were strongly influenced by the weighting function could be obtained. Integrated aerosol properties, such as total surface area and volume, can be retrieved to within 25 and 15% for particles in the size range between 0.1 and 1.0 μm from the SAGE II data using this technique. However, these error estimates must be increased to account for particles lying outside this range. It is these latter parameters which are most directly applicable to global chemistry and climate change studies.¿ 1997 American Geophysical Union