Growth and yield responses of rice (Oryza sativa L.) to soil salinity were studied in six varieties differing in tolerance at the seedling stage. Plants were grown in four-liter pots containing soil treated with sodium chloride at a rate of 5g/pot, 10g/pot and 15g/pot, and control plants were grown without application of sodium chloride. Varieties tolerant at the seedling stage (Kala Rata 1-24 and IR4595-4-1-13) grew well under salinity, but in other tolerant varieties (Nona Bokra and Pokkali) leaf emergence, tillering and plant length were suppressed by salinity at a similar degree as in the sensitive varieties (IR28 and Mangasa) . The decrease in yield was more conspicuous in IR28, Mangasa and Pokkali than in the other three varieties. Yield components responsible for the yield reduction varied: small number of spikelets in IR28 and Pokkali, and high sterility induced by white heads in Mangasa. Sodium concentration of panicle peduncle and flag and the uppermost third leaves at the maturing stage was similar in all the varieties except for Mangasa which showed the lowest sodium concentration. These results supported the assumption that salinity-tolerant varieties at the seedling stage do not always maintain grain yield at a sufficient level under salinity, and indicated that the plant ability to maintain a low level of sodium concentration is not related to salinity tolerance throughout the growth period.