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A lack of salt‐tolerant cultivars may be due in part to inadequate evaluation protocols used for selection. Our objective was to develop a greenhouse protocol that is simple and consistently separates genotypes for their relative ability to survive under saline conditions. In 2000 and 2001, 12 alfalfa ( Medicago sativa L.) cultivars were seeded in 3.8‐ by 21‐cm cone‐shaped containers plugged with capillary matting and filled with silica sand. Six‐week‐old seedlings were submersed in a NaCl‐nutrient solution starting at an electrical conductivity (EC) of 3.0 dS m −1 and increased 3.0 dS m −1 every 1 to 2 wk for 10 to 13 wk. Probit analysis was used to estimate the time and salt dose to reach 50 (LD 50 ) and 75% (LD 75 ) mortality. Probit results were compared with cultivar ranking for mean percentage plant mortality when overall trial mortality reached approximately 50 and 75%. Pearson's rank correlations between 2000 and 2001 at the LD 50 and LD 75 levels were r = 0.90 ( P < 0.001) and r = 0.88 ( P < 0.001), respectively. Rank correlations between 2000 and 2001 based on means when overall trial mortality levels were approximately 50 and 75% were r = 0.92 ( P < 0.001) and r = 0.85 ( P < 0.001), respectively. The correlations between mean percentage cultivar mortality rankings and the probit‐based rankings were above r = 0.90 ( P < 0.001) in both years. The high correlations verify that this protocol produces repeatable results and provides a method to effectively screen large numbers of plants for survival under saline conditions.