The ultimobranchial gland of the mulard duck is a bilateral endocrine organ that is located in the thorax. The current study aimed to describe the topographical, anatomical and histological picture of the ultimobranchial gland in mulard ducks. Eleven healthy adult males of ducks were selected. Gross morphology and histological analysis of ultimobranchial tissue was performed. Grossly, ultimobranchial glands appeared yellow spherical bodies on both sides of the trachea near the syrinx, parallel to the common carotid arteries and cranio-lateral to the junction of the subclavian and common carotid arteries. Each ultimobranchial gland composed of two lobes adhered to each other and appeared as a single gland. Histologically, Ultimobrachial gland had a delicate connective tissue capsule around the gland that composed mainly of Collagenous fibers. The main cells of the glands were parafollicular or C cells which supported by connective tissue stroma. C cells had a columnar shape with centrally located oval nucleus. They were organize in many clusters of various sizes and also a single C-cells were present scattered throughout the stroma of the gland. The C cells showed on reaction with PAS stain, whereas the connective tissue stroma and capsule were reacted positively with PAS stain. This study characterized ultimobranchial gland location, gross anatomy and microscopic features in mulard ducks.