In order to understand the temporal variations and species composition of tintinnids, at two stations of the Korea Strait, this study was carried out from January to December 2007 (n=17). Fifty-one species from 22 genera were encountered: 27 neritic species (9 genera) and 24 oceanic species (14 genera). The species composition was different between two stations, and neritic species frequently appeared at St. 1, while oceanic species more frequently appeared at St. 2. According to the frequency in appearance of species, the most dominant species were neritic species such as Stenosemella nivalis and S. pacifica, that appeared in all seasons. Also, Acanthostomella norvegica, Amphorellopsis acuta, Epilpocyloides ralumensis, Protorhabdonella curta and other many oceanic species appeared intensively during the low salinity (${leqq}33;psu$) and high water temperature (${geqq}24^{circ}C$) period (July~October). The abundance of tintinnids ranged from 0 to 1,845 cells $L^{-1}$. It was higher in the seasons (summer and autumn) of low salinity and high water temperature than in other seasons. The abundance was relatively higher at St. 1 than at St. 2. On the basis of correlation and multiple regression analyses, the tintinnid abundance was not correlated with chi-a, but significantly correlated with water temperature and salinity, suggesting to be the primary abiotic factors influencing the abundance. This study suggests that the complex hydrographic conditions of the study area might influence the temporal distribution and species composition of tintinnids.