Differences in 22Na uptake was determined in contrasting rice cultivars differing in salt tolerance. Selection for contrasting cultivars with significant differences in salt tolerance was based on a preliminary screening and included varietal differences in Na+ exclusion capacity, K/Na selectivity based on K+, Na+ content of roots and shoots and a few other physiological traits. Almost 80 percent of the 22Na uptake, into roots occurred during the first 1 h after salt stress imposition in both varieties. However 22Na uptake was significantly higher in the salt susceptible KMP-175 as compared to Pokkali—in the first hour after salt stress imposition. After 6 and 24 h, the 22Na uptake differences tapered off in the roots while these differences remained up to 6 h in the shoot. Overall the results broadly suggested that plants of the salt tolerant Pokkali were able to regulate Na+ transport into roots, more effectively than the salt susceptible variety immediately upon salt stress imposition but only for short periods.