Abstract. Forty Harderian glands obtained from 20 clinically healthy and sexually mature common pheasants (10 birds of each gender) were investigated. Permanent histological preparations were made from previously fixed glands using routine histological techniques. Morphometric studies were performed by means of a light microscope with a built-in eyepiece micrometer. Data was statistically processed by a computer program (StatMost for Windows). The histometric analysis showed that the average size of pheasant Harderian gland lobules was 399.02 μm and 555.69 μm in female and male common pheasants, respectively. The average outer diameter of the acini was 39.64 μm in the female pheasants and 43.65 μm in the males. The average height of the covering glandular epithelium of the ducts was 18.67 μm in females and 21.41 μm in males. On the basis of our results, it could be concluded that the Harderian gland of the common pheasant by the time of the commercial realization presents a clear sexual dimorphism.