The innervation of the capybara thoracic limb was characterized. The following nerves were observed constituting the right and left brachial plexus: n. dorsalis scapulae (C4 and C5; C4, C5 and C6) which innervates the m. serratus ventralis cervicis and m. rhomboideus; n. suprascapularis (C4, C5 and C6; C5, C6 and C7) supplying the m. supraspinatus and the m. infraspinatus; cranial and caudal nn. subscapulares (C5 and C6; C5, C6 and C7) innervating the m. subscapularis; n. axillaris (C5 and C6; C6, C7 and C8) which supplies the m. triceps brachii (caput mediale); n. radialis (C6, C7, C8 and T1; C6, C7 and C8) which innervates the m. triceps brachii (caput longum and caput mediale) and the m. extensor carpi radialis, m. extensor digitorum communis, m. extensor digitorum lateralis; n. medianus joined to the n. musculocutaneus (C6, C7, C8 and T1; C6, C7 and C8) supplying the m. biceps brachii, m. flexor carpi radialis and m. coracobrachialis; n. ulnaris (C6, C7, C8 and T1; C6, C7 and C8) leading to the m. flexor carpi radialis, the m. flexor carpi ulnaris and the m. flexor digitorum superficialis; n. thoracodorsalis (C6, C7, C8 and T1; C6, C7 and C8) supplying the m. latissimus dorsi; n. thoracicus lateralis (C8, T1; C7, C8, T1) which innervates m. pectoralis profundus (caudal portion); n. thoracicus longus (C6, C7; C7, C8) which is distributed to the m. serratus ventralis thoracis. A communication between the n. radialis and n. ulnaris was observed at the left brachial plexus.