The morphological characteristics between male and female of three species, Chaenogobius urotaenia, C. sp. MR, C. sp. BW, collected from June 1996 to Aug. 1999, Korea was studied. Of 13 characters to be studied, 12 characters with exception of caudal fin ray length were significantly different among three species and these three species were distinguished each other by the results of the multiple comparison test(REGWQ test). Interspecific differences in female was distinct in body depth, head length, caudal peduncle length, caudal peduncle depth, snout length, pectoral fin ray length; In particular, C. sp. MR was shorter in upper jaw length, anal fin ray length and eye diameter, and to be smaller in head depth and head width than other two species. Chaenogobius urotaenia was longer in pelvic fin ray length. In case of male, there was not characters to distinguish each one among three species; Chaenogobius urotaenia was longer in head length, eye diameter and pelvic fin ray length than other two species, C. sp. MR to be longer in caudal peduncle length, but shorter in snout length and anal fin ray length, and to be lower in head depth. C. sp. BW was higher in body depth and caudal peduncle depth, and to be longer in upper jaw length and pectoral fin ray length. Both of male and female among three species didn`t have any difference in caudal fin ray length.