Biochemical changes in leaves of isabgol (Plantago ovata Forsk.) genotypes viz., GI-2, HI-96, PB-80 and HI-5 were studied under salt stress at different EC levels viz., control (without salt), 5 and 10 dS/m of nutrient supplemented NaCl salt solutions in sand filled polythene bags. The results revealed a significant increase in proline with increase of salt stress. Maximum accumulation of proline was found in the genotype GI-2, while minimum in the genotype PB-80. Ascorbic acid content significantly declined with increasing EC levels. Reduction in ascorbic acid content was maximum in the genotype PB-80 and minimum in GI-2. These findings indicate higher tolerance of genotype GI-2 and higher sensitivity of the genotype PB-80 to salt stress among all the genotypes studied.