The problem of assessing the age of unidentified corpses remains a pressing one. Relevant published data is reviewed in brief. This study was aimed at assessing the possibility of using quantitative morphometric parameters of thyroid involution for forensic medical evaluation. The method of using these parameters and their mathematical processing is described. An optimal model is selected for assessing the biological age from two parameters, the percentage and diameter of follicles; this model permits the diagnosis of age with an accuracy of 88%.