The purpose of this study was to clarify if symptomatic osteoporosis is a risk factor for severe residual ridge reduction of the jaws. The analysis included 12 edentulous women with osteoporotic fractures, otherwise normal, and 16 normal edentulous women matched with respect to age, menopausal age, and period of edentulousness. The bone mineral content measured in vivo by dual-photon scanner was significantly lower in the mandible and the forearm bones (that is, in the skeleton) of the osteoporotic group than it was in the normal group. No significant difference between the two groups was demonstrated with respect to the size of the mandibular sagittal area, measured on identical lateral cephalograms, while the sagittal maxillary area was significantly smaller in the osteoporotic group. Symptomatic osteoporosis therefore seems to be a severe risk factor for smaller residual ridge reduction off the maxillae, while this does not seem to be the case in the mandible.