Soil salinity is one of the major constraints affecting rice production worldwide. Goal of this research was evaluation of salt tolerance of new mutant rice germplasm and characterization of new salttolerant mutant rice promising lines with superior qualitative and quantitative traits. Salt tolerance of 56 promising mutant rice lines and 8 commercial and standard cultivars was investigated on standard evaluation scale of IRRI in an Augmented Design in salt affected soils of a rice farm with EC 6.5 dSm-1 in Pirbazar region of Rasht, Guilan province of Iran