To understand the function of nursery grounds, the seasonal variation of ichthyoplankton was investigated in the East Sea, off Dokdo, from September 2009 to May 2010. The dominant species was Engraulis japonicus (92.7%), which occurred in May and September. The next abundant species was Maurolicus japonicus (5.7%), found in all four seasons. Several rare warm-water species were found in September and November, when the species diversity was higher than in the other two seasons. Several fish species used Dokdo as a nursery ground for a restricted season, while M. japonicus used it in all four seasons.