Abstract: Experiments were conducted to evaluate allelopathic influence of eucalyptus on the germination and seedling growth of cotton, sunflower, sorghum, mungbean and mothbean under the laboratory conditions. One kg of fresh leaves of eucalyptus was soaked in ten liter of water for 72 hours. This extract was used in seeds soaking prior to sowing in the pure sand culture. The same extract was applied to the germinated seeds in comparison with simple water application to the control treatments. The results revealed that application of aqueous extract of fresh leaves to seeds of all crops reduced the germination and suppressed the growth of roots and shoots of seedlings of crops belonging to different families.