Petroleum ether and acetone extracts of Citrus aurantifolia Swingle seeds were tested against Toxocara vitulorum (Ascaris), and Fasciola gicantica {larvae and Eggs), Trihconstronylus colubriformis{adult worms , larvae and Eggs), larvae of Trichinella spiralis , in addition to Eimeria oocyst .The results revealed variation in the lethal effect with different organisms. Petroleum ether(40-60) extract tested at 100% concentration showed 100 % mortality effect against all parasites except T. colubriformis. larvae (39. 6% mortality) .The larvicidal effect of acetone extract vary from  T. colubriformis (adult worms) , F. gicantica (mature fluks) and T.spiralis larvae (LC 50 = 415,522,630 ppm ) respectively, but no effect was observed against ascaris (adult worms) or T. colubriformis (larvae). Acetone extract was effective against the eggs of T.vitulorum, F. gicantica and T. colubriformis (LC₅₀ 275, 155, 309 ppm) respectively. Also, an oocidal effect was observed against Eimeria  (LC50 = 631 ppm) Phytochemical study of the bioactive extracts lead to identification of limonin and limonexic acid beside nine coumarins  from acetone extract, the isolated compounds were identified by chemical  and spectral analysis. The petroleum ether extract was saponified and analyzed by GC/Mass.