Objective To investigate and compare the biological characteristics and sensitivity to chemotherapy and radiother-apy of intrahepatic and extrahepatie cholangiocarcinoma cells in vitro.Methods The intrahepatic and extrahepatie eholangiocarcinoma cell lines were established, and cells with steady passage were chosen to study the biological characteristics including morphology, growth dynamics, chromosome, and levels of cancer antigen (CA)125, CA 19-9, alpha-fetoprotein (AFP), and carcino-embryonic antigen (CEA).M.eanwhile, MTT assay was used to determine the sensitivity of both kinds of cells to 6 chemotherapeutic drugs, inclu-ding cisplatin, paclitaxel, harringtonine, 5-fluorouracil, vincristine, and aelacimomycin, and the inhibitory rate of ceils under the irradiation of 10 Gy ray was also measured.Reanlts The intrahepatic cholangiocarcinoma cells were mostly fusiform in shape, and extrahepatic eholangiocar-cinoma cells were mostly round or polygon in shape. Their doubling time was 26. 3 hours and 23.1 hours, respectively.Their average number of chromosomes was 59 (range, 38-84) and 67 (range, 49-103 ), respectively. The chromo-some karyotypes of most intrahepatlc ebolangiocarcinoma cells were hyperdiploid and hypotriploid, while hypertriploid was predominant in extrahepatic cholangioearcinoma cells. The level of CA 125 in supernatant of extrahepatic cholangio-carcinoma cells increased obviously, while levels of other determined tumor markers in both kinds of cells were all with-in normal range. The intrahepatic cholangiocarcinoma cells were low sensitive to cisplatin and paclitaxel, but not sensi-tive to the other 4 chemotherapeutic drugs. The extrahepatic cholangiocarcinoma cells were high sensitive to eisplatin,but not sensitive to the other 5 drugs. Both kinds of cells had poor sensitivity to radiotherapy.Conelusions Intrahepatic and extrahepatie cbolangiocareinoma cells show differences in shape, doubling time,chromosome karyotype, tumor marker level, and chemosensitivity, whereas they both have poor radiosensitivity.Though they are similar in histopathology, they have different growth characteristics and have discrepancy in treatment and prognosis.