The aim of this study to evaluate the histopathological, histochemical and immunohistochemical changes of the endocrine glands namely, thyroid, pancreas and adrenal gland in dogs submitted to routine necropsy. A total number of 45 endocrine samples were collected from 15 carcasses of dogs received at Department of Veterinary Pathology, Madras Veterinary College, Chennai- 600 007 were chosen for the present study, namely thyroid, pancreas and adrenal gland. The tissue samples were collected in 10% neutral buffered formalin. Tissues were processed after 48 hours as per recommended procedure and 3 µm thickness sections were made and stained with haematoxylin and eosin for histopathological evaluation. The special stains like Masson’s trichrome and Picrosirius red were used to assess the extent of replacement with collagen fibers. Immunohistochmical protocol was followed as per the manufactured recommendation (Pathnsitu, USA).The histopathological changes recorded in the pancreas included vacuolar changes (2/15), necrosis (2/15), periductular fibrosis (1/15), perivascular fibrosis (1/15), congestion (5/15), hemorrhages (3/15) and inflammatory changes (1/15) while in the adrenal glands included diffuse cortical hyperplasia (4/15) succeeded by nodular hyperplasia (3/15), adrenalitis (2/15), hyperaemia (2/15), hemorrhages (1/15) and atrophy (1/15). Histopathological examination of thyroid revealed atrophy of follicles suggesting thyroiditis (3/15), presence of follicular epithelial cells which were found separated from the basement membrane with cellular debris in the lumen indicating necrosis (2/15) and presence of large cystic gaps with eosinophilic proteinaceous material consistent with cystadenoma(2/15). The remaining samples showed hemorrhages (2/15), perivascular fibrosis (1/15) and congestion (2/15). However no histological alterations were noticed in 3 cases (3/15). Immunohistochemistry revealed that pancytokeratin was expressed by all epithelial cells including ducts. The expression of insulin was noticed in all the cases indicating that no reduction of â cells in all the above said pathological conditions.