During routine dissection for Ist MBBS students on 65 year old donated embalmed male cadaver in the Department of Anatomy, K.J.Somaiya Medical College, Sion, Mumbai, India, we observed an unusual branch of the brachial artery. The brachial artery terminated in the cubital fossa into radial and common interosseous arteries. The radial artery had normal course and branches. The common interosseous artery was deeper and gave anterior and posterior ulnar recurrent arteries, and terminated into anterior and posterior interosseous arteries. The unusual large branch from the brachial artery was a variant of ulnar artery, arose from the lateral side of the brachial artery, descended on the lateral side upto the cubital fossa and crossed the fossa from lateral to medial, superficial to median nerve. It then descended superficial to the muscles arising from medial epicondyle of the humerus and was covered by the deep fascia of the forearm, pierced the deep fascia proximal to the wrist, crossed the flexor retinaculum, and formed the superficial palmar arch. Throughout its course, this artery gave no branch. There were no associated altered anatomy of the nerves observed in the specimen. The left upper limb of the same cadaver was normal. The photographs of the variations were taken for proper documentation and for ready reference. The embryological basis of the variation is presented.