Modern imaging methods make possible the more precise examination of the complicated bony structure of the temporomandibular joint (TMJ) and the performance of cephalometric analysis. The aim of our study was to analyse the effect of edentulousness on the mandibular size and the condyle-fossa position using roentgencephalograms and axial computed tomography (CT) scans. The study group consisted of 20 edentulous patients (14 women, six men, mean age 60 years) whose mean period of edentulousness was 20 years (range 3-34 years). A CT examination of their TMJs was performed and roentgen-cephalograms in 16 of this group were taken after prosthetic treatment. Sixteen dental students were chosen according to sex as controls. Earlier CT scans of 49 dentate subjects of both sexes were used as controls for the analysis of bicondylar asymmetry. The position of the glenoid fossa was more anterior in edentulous subjects than in dentate ones and its anterior position correlated significantly (P < 0.02) with the period of edentulousness, a finding which has not been confirmed before. It can be concluded that the fossa is a remodelling unit as a part of the functional entity when the function is altered dramatically as in the case of edentulous patients.