Abstract: A field experiments were conducted at NARC, Islamabad during 1988-89 and 1989-90, with Waster rapeseed (Brassica napus L.) to determine the effect of topping at different growth stages on seed quality. Topping treatments included an untopped check, the removal of three-quarters of the top growth at each of pre-bud, bud and first flower, as well as removal of all secondary branches at first flower. Although topping showed positive response on oil content (%) in seed in all trials which ranged 43.9 to 48.0% which appeared non significant on erucic acid and glucosinolates in the seed.