Among the oilseed Brassica crops, Indian mustard [Brassica juncea (L.) Czern and Coss.] is an important source of oil from a nutritional point of view. The nutritional value of oil and cake quality is governed mainly by the composition of its fatty acids, iodine value, saponification, acid value, glucosinolates, crude fibre, protein and limiting amino acids, etc. Seventeen varieties/strains of Indian mustard were taken for saturated and unsaturated fatty acid analysis. The eicosenoic was absent in genotype (NUDBYJ-10) and erucic acid (NUDBYJ-10, LES-46 and Pusa mustard- 21). The fatty acid composition found a variable in different genotypes. Saturated fatty acid, Palmitic + Stearic ranged between 2.3 to 6.5%, Oleic 10.6 to 40.7%, Linoleic 16.1 to 37.7%, Linolenic 13.3 to 26.7%, Eicosenoic 0.00 to 10.30% and Erucic acid 0.00 to 47.50%, respectively. Alternaria blight severity also varied in different genotypes and ranged between 18.75 to 56.25%, maximum being in genotype Kranti and minimum in LES-47. No significant correlation was observed between the fatty acid composition and disease severity. The oil content range from 38.1 to 42.60% and protein content was found highest in variety RGN-73. The amino acid viz. methionine and tryptophan range between 0.41 to 1.81 g/16gN and 0.41 to 1.81 g /16g N, respectively.