| Pakistan had to devour huge money on the import of edible oil. Aphids are the most notorious insect pests of Brassica crops in Pakistan and throughout the world as well. Host plant resistance is one of the most useful tools for the management of aphids in Brassica crop. This trial was executed at the farm of Regional Agricultural Research Institute, Bahawalpur to report the impact of aphid damage on yield and yield parameters on Brassica juncea . Five varieties/strains i.e. BRJ-9070, BRJ-9072, BRJ-1004, BRJ-1104 and KP Raya were grown in two sets with Randomized Complete Block Design (RCBD) and there were three replications. No pesticides used on untreated block and natural populations of aphids were allowed to develop to estimate losses while and aphid population was recorded every 10 days intervals, while the treated blocks were kept free from aphids by the use of carbosulfan @ 400 ml/acre. At crop maturity, crop parameters like plant height (cm), number of silique per plant, yield loss in unsprayed blocks was compared to the yield of pesticide sprayed blocks. The yield components and yield in the insecticide free plots were much lower than that of insecticide sprayed plots which were kept aphid free. Maximum percentage reduction (14%) in plant height was observed on BRJ-9072, the silique per plant loss percentage was maximum on KP-raya (36.97%), whereas maximum percentage loss of yield per hectare (70.77%) was observed on BRJ-1104. Application of insecticide would still be required for the control of aphids as the current varieties lack complete or sufficient resistance against them.