The dual innervation of the brachialis muscle by the musculocutaneos nerve and branches from the radial nerve has been described by some anatomical texts and several scientific papers; however, there is no consensus about the frequency with which this occurs. In this study we proposed to check the presence and determine the frequency of the contribution of radial nerve in the innervations of the brachialis muscle. In this study we used 30 upper limbs fixed in fixative and conservative solution. Dissection of the brachial region was carried out, checking the branches that penetrated the muscle and taking samples of these branches to histological study. It was possible to observe the presence of branches of the radial nerve innervating the brachialis muscle in a 90% of the sample used in this study; the motor point of these branches was always located in the distal third of this muscle. According with the results of this study, the dual innervations of the brachial muscles observed by classical authors and reported by several investigations is also present in a high percentage of the sample. These findings can serve as reference for surgical procedures, electromyographic and ultrasound studies.