Neoplasms of unknown primary site are tumor diseases, which are diagnosed by the pathologic studies of one of their metastases. The treatment of neoplasms of unknown primary site is not totally established, except in a few situations with specific therapeutical implications, and a better prognosis. The usual treatment of neoplasms of unknown primary site is the empirical chemotherapy with taxanes (paclitaxel or docetaxel) and platines (cisplatin or carboplatin)-based regimens, with different results in the trials.