The microstructural characteristics of titanium dioxide aerogels were studied with small-angle neutron scattering (SANS). A variety of models were used to extract the morphological parameters from the SANS data. The scattering data were interpreted in terms of a model that consists of nanocrystallites of TiO2 that are densely packed in mesoaggregates. This model is consistent with nitrogen gas adsorption and transmission electron microscopy (TEM) measurements. The particle size distribution was fit to a log-normal distribution and maximal entropy method(MEM). The structure-related geometrical parameters are discussed.