The fact that Rivulus marmoratus, a hermaphroditic fish, could survive such adverse environments as wide range pH (3.5-11.5), excess H₂S, typhoon, dryness, and low oxygen, suggests that this fish may have stringent defense mechanisms to the diverse environmental stresses. As an effort to elucidate the defence mechanisms for the environmental stresses as well as to develop a fish model to study early development and differentiation at the molecular level, we demonstrated the molecular cloning of stress protein-coding gene. Three positive clones for the human hsp 70 cDNA probe were initially screened out from the R. marmoratus genomic clone bank by using shot gun plague hybridization protocol. We finished 11 kb nucleotide sequencing from one clone which had 14 kb insert DNA. By homology search of the sequenced nucleotides to the known data library, it was turned out that this clone contained the full length R. marmoratus hsc 70 gene that consisted of 9 exons and 8 introns, within 7 kb long. The gene structure as well as nucleotide and the deduced amino acid sequences were quite homologous to those known in other fish. Data for the developmental, tissue-specific expression profile as well as stress-inducability of R. marmoratus hsc 70 gene will also be presented.