In the present study the allelopathic potential of invasive plant weed Goniocaulon indicum C. B. Clarke. on seed germination and seedling growth of maize (Zea mays L.) and wheat (Triticum aestivum L.) has studied. The aqueous extracts of G. indicum root, stem, leaves and whole plant at 05%, 10%, 15 and 20%; leachates of root, stem, leaves and whole plant at 05%, 10%, 15 and 20%; root zone soils of G. indicum was to evaluated. The allelopathic pattern varied in each of the tests and this depends upon type of test material. The lowest seed germination has been observed at highest concentration (20%) of whole plant in both aqueous extracts and leachates. But radicle and plumule length of wheat seedlings were more hampered in soil collected beneath the root zone of G. indicum. It is interesting to note that all bioassays of the weed noticeably inhibited the germination and seedling growth of maize and wheat. To prove the allelopathic effect of root zone soil of G. indicum, the soil was analyzed to obtain the values of pH, EC, organic carbon, nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, zinc, manganese, boron, copper, sodium and free calcium carbonate. The root zone soil shows decreased amount of nitrogen, phosphorus, iron and very high amount of potassium and free calcium carbonate.