Abstract: Brassica juncea (L.) Czern var. Ensabi is a new local variety of mustard species, found only in Sabah and Sarawak, Malaysia. Electrophoretic characterization of plant proteins during development would be of great interest for comparison to other varieties of Brassica species. This study has been conducted to analyze protein profiles of B. juncea var. Ensabi at different growth stages. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of seed, shoot and root samples of seedling, before-flowering and after-flowering stages of the plant were performed on 10% polyacrylamide gel. Molecular weights of fractionated proteins were determined from a standard plot of log molecular weight versus relative mobility of marker proteins. Five polypeptides of ~66, 54, 39, 34 and 23 kDa, out of 11 protein bands noticed in seed proteins of Ensabi, matched closely with seed storage protein profiles of other varieties of B. juncea. The 29 kDa seed protein, commonly found in B. juncea (L.) Czern was also identified in Ensabi as S8. This protein expressed steadily in shoot samples at all growth stages. Interestingly, two seed proteins, S5 (~54 kDa) and S10 (~23 kDa) were remained expressed in both shoot and root samples throughout the plant development. Both common and unique proteins appeared at different growth stages of the plant. A comparison of the protein profiles at different growth stages suggested steady expression as well as up- and down-regulation of several genes encoding different proteins in B. juncea var. Ensabi.