Brachial plexus dysfunction is a well-known complication of cancer. Metastatic brachial plexus (RBP) are the most common causes. The distinction between MBP and RBP is very important but is not easy to make. This article presents in detail the distinguishing features of these types of brachial dysfunction. In regard to treatment, radiation, chemotherapy, narcotic analgesics, paravertebral nerve blocks, dorsal rhizotomy, dorsal root entry zone procedure, and high contralateral cordotomy are helpful in managing the symptoms of MBP. Transdermal electrical nerve stimulation, dorsal column stimulators, neurolysis, and neurolysis with omentoplasty have been tried in RBP. Good physical therapy, tricyclics, antiarrhythmics, anti-convulsants, nonsteroidal anti-inflammatory drugs and steroids are helpful in both conditions.