In the present study, the efficacy of a nerve stimulator in performing brachial plexus block (BPB) in dogs was investigated. The nerve blocking effects of bupivacaine and ropivacaine for BPB were also compared. Twelve beagles were allocated to groups based on the following treatments: conventional BPB with 0.5% bupivacaine (0.5% BupiM group) or BPB with 0.5% bupivacaine, 0.5% ropivacaine or 0.75% ropivacaine and a nerve stimulator (the 0.5% BupiS, 0.5% RopiS and 0.75% RopiS groups, respectively). After BPB, nerve blocking effects were assessed based on sensory blockade in several cutaneous areas and knuckling. The ratio of full block (blockade in all cutaneous areas) for 0.5% BupiM was 25%, and that for 0.5% BupiS was significantly higher, 75% (p<0.05). For the 0.5% BupiS, 0.5% RopiS and 0.75% RopiS groups, the average duration of full block was 387, 184 and 275 min, respectively, and the average duration of knuckling was 703, 460 and 421 min, respectively. The duration of full block and knuckling for the two ropivacaine groups was shorter compared with that of the 0.5% BupiS group. In conclusion, when using bupivacaine and ropivacaine for BPB in dogs, it is worth noting that there are differences in onset time and duration and that effective perioperative analgesia can be achieved depending on the intended use.