A relatively simple and reliable in vitro method for marine fish chromosome study was developed. The addition of 10% chick embryo extract to serum-supplemented Eagle's minimum essential medium with high concentration of NaCl resulted in marked growth of kidney cells in the marine conger eel (Astroconger myriaster) after activation by phytohemagglutinin (PHA). Culture medium without chick embryo extract or PHA and/or with normal concentration of NaCl did not induce substantial growth. In contrast to reports by others, humidified culture was not required for excellent cell growth of these teleost kidney cells. Numerous metaphases unmarred by overlapping chromosomes were recovered and excellent karyograms were available for detailed karyotype analysis.Key words: kidney, culture, marine fish, chromosome