Spirulinaplatensis. The results showed that, the highest significant increment forgrowth and yield characters was resulted from the treatment of algae extract +biofertilizer + 15m3 compost this combination treatment resulted in the highestmean value of oil yield (ml/ plant). As general the main chemical constituentsof oregano essential oil were carvacrol, p-cymene, ç-terpinene,α-thujene, α-myrcene,α-terpinene, o-cymene, carvacrol methyl ether andcaryophyllene.