Rice is one of the most important and high economic value food crops in Vietnam. Due to the global clime change, the negative effects of salted soil on yield and quality of rice have become more seriously; therefore, the enhancement in salt tolerant rice is always the research topic of interest. HKT (high affinity potassium transporter) is a protein family which plays role in ion transport in plants. It is proven that HKT proteins involve in ion Na+ influx and salt tolerance in rice plants. In this study, the expression level of OsHKT2;1 gene coding HKT protein in rice was investigated using semi-quantitative RTPCR technique. Experiments were conducted on two rice cultivars, including Nipponbare (the standard salt sensitive cultivar) and Pokkali (the standard salt resistant culativar) with two different salt concentrations of 50 mM and 100 mM NaCl for different periods of exposure time (24, 48, and 72 hrs of salt treatment). The results showed that in Nippobare cultivar the expression level of OsHKT2;1 gene was increased after 24 hours of 100 mM-salt treatment, but decreased to normal level after 72 hours of treatment. However, the OsHKT2;1 expression level was unchanged over different salt stress conditions and at different time periods in Pokkali cultivar. In control condition, the expression level of OsHKT2;1 gene in leaves of Nipponbare was higher than that in Pokkali. It might be likely that the differences in OsHKT2;1 gene expression level involve in the differences in salt tolerance in two investigated rice cultivars. The results of initial studies provide useful information for salt tolerant rice breeding in the future.